Fusion formable and steam strengthenable glass compositions with platinum compatibility

ABSTRACT

Glass-based articles that include a compressive stress layer extending from a surface of the glass-based article to a depth of compression are formed by exposing glass-based substrates to water vapor containing environments. The glass-based substrates have compositions selected to be fusion formable, to be steam strengthen able, and to avoid the formation of platinum defects during the forming process. The methods of forming the glass-based articles may include elevated pressures and/or multiple exposures to water vapor containing environments.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.17/327870 filed on May 24, 2021, which is a continuation ofInternational Patent Application Serial No. PCT/US2021/031524 filed onMay 10, 2021, which claims the benefit of priority to under 35 U.S.C. §119 of U.S. Provisional Application Ser. No. 63/023,518, filed May 12,2020, the contents of which are relied upon and incorporated herein byreference in their entirety.

BACKGROUND Field

This disclosure relates to glass-based articles strengthened by steamtreatment, glass compositions utilized to form the glass-based articles,and methods of steam treatment to strengthen the glass-based articles.

Technical Background

Portable electronic devices, such as smartphones, tablets, and wearabledevices (such as, for example, watches and fitness trackers), continueto get smaller and more complex. As such, materials that areconventionally used on at least one external surface of such portableelectronic devices also continue to get more complex. For instance, asportable electronic devices get smaller and thinner to meet consumerdemand, the display covers and housings used in these portableelectronic devices also get smaller and thinner, resulting in higherperformance requirements for the materials used to form thesecomponents.

Accordingly, a need exists for materials that exhibit higherperformance, such as resistance to damage, along with lower cost andease of manufacture for use in portable electronic devices.

SUMMARY

In aspect (1), a glass-based article is provided. The glass-basedarticle comprises: a compressive stress layer extending from a surfaceof the glass-based article to a depth of compression, ahydrogen-containing layer extending from the surface of the glass-basedarticle to a depth of layer, and a composition at the center of theglass-based article, comprising: SiO₂, Al₂O₃, K₂O, R₂O/Al₂O₃ in anamount that is less than or equal to 1.4, wherein R₂O is the totalamount of monovalent metal oxides, greater than or equal to 3.5 mol % toless than or equal to 6.0 mol % P₂O₅, and greater than or equal to 2.0mol % to less than or equal to 5.0 mol % Li₂O. The compressive stresslayer comprises a compressive stress greater than or equal to 25 MPa, ahydrogen concentration of the hydrogen-containing layer decreases from amaximum hydrogen concentration to the depth of layer, and the depth oflayer is greater than 5 μm.

In aspect (2), the glass-based article of aspect (1) is provided,further comprising a fusion line.

In aspect (3), the glass-based article of aspect (1) or (2) is provided,wherein the glass-based article comprises less than 1 globular chainplatinum defect per pound.

In aspect (4), the glass-based article of aspect (1) or (2) is provided,wherein the glass-based article exhibits no substantial phaseseparation.

In aspect (5), the glass-based article of any one of aspects (1) to (4)is provided, wherein the composition at the center of the glass-basedarticle further comprises B₂O₃.

In aspect (6), the glass-based article of any one of aspects (1) to (5)is provided, wherein the composition at the center of the glass-basedarticle further comprises Na₂O.

In aspect (7), the glass-based article of any one of aspects (1) to (6)is provided, wherein the composition at the center of the glass-basedarticle further comprises SnO₂.

In aspect (8), the glass-based article of any one of aspects (1) to (7)is provided, wherein the composition at the center of the glass-basedarticle has an average field strength of alkali modifiers that is lessthan or equal to 0.18.

In aspect (9), the glass-based article of any one of aspects (1) to (8)is provided, wherein the composition at the center of the glass-basedarticle comprises: greater than or equal to 55.0 mol % to less than orequal to 65.0 mol % SiO₂, greater than or equal to 10.0 mol % to lessthan or equal to 15.0 mol % Al₂O₃, greater than or equal to 0 mol % toless than or equal to 10.0 mol % B₂O₃, and greater than or equal to 6.0mol % to less than or equal to 15.0 mol % K₂).

In aspect (10), the glass-based article of any one of aspects (1) to (9)is provided, wherein the composition at the center of the glass-basedarticle comprises greater than or equal to 4.5 mol % to less than orequal to 5.5 mol % P₂O₅.

In aspect (11), the glass-based article of any one of aspects (1) to(10) is provided, wherein the composition at the center of theglass-based article comprises greater than 0 mol % to less than or equalto 3.0 mol % B₂O₃.

In aspect (12), the glass-based article of any one of aspects (1) to(11) is provided, wherein a glass having the same composition as thecomposition at the center of the glass-based article has a zirconbreakdown viscosity of less than or equal to 35 kP.

In aspect (13), the glass-based article of any one of aspects (1) to(12) is provided, wherein a glass having the same composition as thecomposition at the center of the glass-based article has a liquidusviscosity of greater than or equal to 100 kP.

In aspect (14), the glass-based article of any one of aspects (1) to(13) is provided, wherein the glass-based article has a substantiallyhaze-free appearance.

In aspect (15), the glass-based article of any one of aspects (1) to(14) is provided, wherein the depth of compression is greater than 5μm.

In aspect (16), the glass-based article of any one of aspects (1) to(15) is provided, wherein the compressive stress layer comprises acompressive stress greater than or equal to 200 MPa.

In aspect (17), the glass-based article of any one of aspects (1) to(16) is provided, wherein the composition further comprises 1.4<(R₂O+P₂O₅)/Al₂O₃<1.9, wherein R₂O is the total amount of monovalentmetal oxides.

In aspect (18), a consumer electronic product is provided. The consumerelectronic product comprises: a housing comprising a front surface, aback surface and side surfaces; electrical components at least partiallywithin the housing, the electrical components comprising at least acontroller, a memory, and a display, the display at or adjacent thefront surface of the housing; and a cover substrate disposed over thedisplay. At least a portion of at least one of the housing or the coversubstrate comprises the glass-based article of any one of aspects (1) to(17).

In aspect (19), a glass-based article is provided. The glass-basedarticle comprises: a compressive stress layer extending from a surfaceof the glass-based article to a depth of compression, ahydrogen-containing layer extending from the surface of the glass-basedarticle to a depth of layer, and a composition at the center of theglass-based article, comprising: SiO₂, Al₂O₃, K₂O,1.4<(R₂O+P₂O₅)/Al₂O₃<1.9, wherein R₂O is the total amount of monovalentmetal oxides, greater than or equal to 3.5 mol % to less than or equalto 6.0 mol % P₂O₅, and greater than or equal to 2.0 mol % to less thanor equal to 5.0 mol % Li₂O. The compressive stress layer comprises acompressive stress greater than or equal to 25 MPa, a hydrogenconcentration of the hydrogen-containing layer decreases from a maximumhydrogen concentration to the depth of layer, and the depth of layer isgreater than 5μm.

In aspect (20), the glass-based article of aspect (19) is provided,wherein the glass-based article comprises less than 1 globular chainplatinum defect per pound.

In aspect (21), the glass-based article of aspect (19) or (20) isprovided, wherein the glass-based article exhibits no substantial phaseseparation.

In aspect (22), a glass-based article is provided. The glass-basedarticle comprises: a compressive stress layer extending from a surfaceof the glass-based article to a depth of compression, ahydrogen-containing layer extending from the surface of the glass-basedarticle to a depth of layer, and a composition at the center of theglass-based article, comprising: SiO₂, Al₂O₃, K₂O,1.4<(R₂O+P₂O₅)/Al₂O₃<1.9, wherein R₂O is the total amount of monovalentmetal oxides, and greater than or equal to 3.5 mol % to less than orequal to 6.0 mol % P₂O₅. The compressive stress layer comprises acompressive stress greater than or equal to 25 MPa, a hydrogenconcentration of the hydrogen-containing layer decreases from a maximumhydrogen concentration to the depth of layer, and the depth of layer isgreater than 5 μm.

In aspect (23), the glass-based article of aspect (22) is provided,wherein the glass-based article comprises less than 1 globular chainplatinum defect per pound.

In aspect (24), the glass-based article of aspect (22) or (23) isprovided, wherein the glass-based article exhibits no substantial phaseseparation.

In aspect (25), a method is provided. The method comprises exposing aglass-based substrate to a treatment environment with a pressure greaterthan or equal to 0.1 MPa, a water partial pressure of greater than orequal to 0.05 MPa, and a temperature greater than 85° C. to form aglass-based article. The glass-based substrate comprises: SiO₂, Al₂O₃,K₂O, R₂₀/Al₂O₃ in an amount that is less than or equal to 1.4, whereinR₂O is the total amount of monovalent metal oxides, greater than orequal to 3.5 mol % to less than or equal to 6.0 mol % P₂O₅, and greaterthan or equal to 2.0 mol % to less than or equal to 5.0 mol % Li₂O. Theglass-based article comprises: a compressive stress layer extending froma surface of the glass-based article to a depth of compression, thecompressive stress layer comprising a compressive stress greater than orequal to 25 MPa, a hydrogen-containing layer extending from the surfaceof the glass-based article to a depth of layer, a hydrogen concentrationof the hydrogen-containing layer decreases from a maximum hydrogenconcentration to the depth of layer, and the depth of layer is greaterthan 5 μm.

In aspect (26), the method of aspect (25) is provided, wherein thetreatment environment is a saturated steam environment.

In aspect (27), the method of aspect (25) or (26) is provided, whereinthe treatment environment has a pressure greater than or equal to 1 MPa.

In aspect (28), the method of any one of aspects (25) to (27) isprovided, wherein the treatment environment has a temperature greaterthan or equal to 150° C.

In aspect (29), the method of any one of aspects (25) to (28) isprovided, further comprising producing the glass-based substrate by afusion forming process.

In aspect (30), the method of any one of aspects (25) to (29) isprovided, wherein the glass-based substrate is not subjected to anion-exchange treatment with an alkali ion source.

In aspect (31), the method of any one of aspects (25) to (30) isprovided, wherein the glass-based substrate further comprises B₂O₃.

In aspect (32), the method of any one of aspects (25) to (31) isprovided, wherein the glass-based substrate further comprises Na₂O.

In aspect (33), the method of any one of aspects (25) to (32) isprovided, wherein the glass-based substrate further comprises SnO₂.

In aspect (34), the method of any one of aspects (25) to (33) isprovided, wherein the glass-based substrate has an average fieldstrength of alkali modifiers that is less than or equal to 0.18.

In aspect (35), the method of any one of aspects (25) to (34) isprovided, wherein the glass-based substrate comprises: greater than orequal to 55.0 mol % to less than or equal to 65.0 mol % SiO₂, greaterthan or equal to 10.0 mol % to less than or equal to 15.0 mol % Al₂O₃,greater than or equal to 0 mol % to less than or equal to 10.0 mol %B₂O₃, and greater than or equal to 6.0 mol % to less than or equal to15.0 mol % K₂O.

In aspect (36), the method of any one of aspects (25) to (35) isprovided, wherein the glass-based substrate comprises greater than orequal to 4.5 mol % to less than or equal to 5.5 mol % P₂O₅.

In aspect (37), the method of any one of aspects (25) to (36) isprovided, wherein the glass-based substrate comprises greater than 0 mol% to less than or equal to 3.0 mol % B₂O₃.

In aspect (38), the method of any one of aspects (25) to (37) isprovided, wherein the glass-based substrate comprises a fusion line.

In aspect (39), the method of any one of aspects (25) to (38) isprovided, wherein the glass-based substrate comprises less than 1globular chain platinum defect per pound.

In aspect (40), the method of any one of aspects (25) to (39) isprovided, wherein the glass-based substrate has a zircon breakdownviscosity of less than or equal to 35 kP.

In aspect (41), the method of any one of aspects (25) to (40) isprovided, wherein the glass-based substrate has a liquidus viscosity ofgreater than or equal to 100 kP.

In aspect (42), the method of any one of aspects (25) to (41) isprovided, wherein the glass-based article has a substantially haze-freeappearance.

In aspect (43), the method of any one of aspects (25) to (42) isprovided, wherein the depth of compression is greater than 5 μm.

In aspect (44), the method of any one of aspects (25) to (43) isprovided, wherein the compressive stress layer comprises a compressivestress greater than or equal to 200 MPa.

In aspect (45), a glass is provided. The glass comprises: greater thanor equal to 55.0 mol % to less than or equal to 65.0 mol % SiO₂, greaterthan or equal to 10.0 mol % to less than or equal to 15.0 mol % Al₂O₃,greater than or equal to 0 mol % to less than or equal to 10.0 mol %B₂O₃, greater than or equal to 6.0 mol % to less than or equal to 15.0mol % K₂O, greater than or equal to 3.5 mol % to less than or equal to6.0 mol % P₂O₅, greater than or equal to 2.0 mol % to less than or equalto 5.0 mol % Li₂O, and 1.4<(R₂O+P₂O₅)/Al₂O₃<1.9, wherein R₂O is thetotal amount of monovalent metal oxides.

In aspect (46), the glass of aspect (45) is provided, comprising anaverage field strength of alkali modifiers that is less than or equal to0.18.

In aspect (47), the glass of aspect (45) or (46) is provided, comprisinggreater than or equal to 4.5 mol % to less than or equal to 5.5 mol %P₂O₅.

In aspect (48), the glass of any one of aspects (45) to (47) isprovided, further comprising B₂O₃.

In aspect (49), the glass of any one of aspects (45) to (48) isprovided, further comprising greater than 0 mol % to less than or equalto 3 mol % B₂O₃.

In aspect (50), the glass of any one of aspects (45) to (49) isprovided, further comprising Na₂O.

In aspect (51), the glass of any one of aspects (45) to (50) isprovided, further comprising greater than or equal to 0 mol % to lessthan or equal to 11 mol % Na₂O.

In aspect (52), the glass of any one of aspects (45) to (51) isprovided, further comprising SnO₂.

In aspect (53), the glass of any one of aspects (45) to (52) isprovided, comprising a zircon breakdown viscosity of less than or equalto 35 kP.

In aspect (54), the glass of any one of aspects (45) to (53) isprovided, comprising a liquidus viscosity of greater than or equal to100 kP.

These and other aspects, advantages, and salient features will becomeapparent from the following detailed description, the accompanyingdrawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of a cross-section of a glass-based articleaccording to an embodiment.

FIG. 2A is a plan view of an exemplary electronic device incorporatingany of the glass-based articles disclosed herein.

FIG. 2B is a perspective view of the exemplary electronic device of FIG.2A.

FIG. 3 is a plot of the saturation condition for water as a function ofpressure and temperature.

FIG. 4 is a plot of the number of globular chain platinum defects perpound of glass as a function of phosphorous content.

FIG. 5 is a microscopy image of a globular chain platinum defect in aglass.

FIG. 6A is a plot of diffuse scattering in transmission vs. wavelengthfor a glass composition, according to an embodiment of the disclosure,and comparative glass compositions.

FIG. 6B is a plot of the scatter ratio vs. wavelength for a glasscomposition, according to an embodiment of the disclosure, andcomparative glass compositions.

FIGS. 7A and 7B are scanning electronic microscopy (SEM) images of twocomparative glass compositions with evidence of phase separation.

DETAILED DESCRIPTION

In the following description, like reference characters designate likeor corresponding parts throughout the several views shown in thefigures. It is also understood that, unless otherwise specified, termssuch as “top,” “bottom,” “outward,” “inward,” and the like are words ofconvenience and are not to be construed as limiting terms. Unlessotherwise specified, a range of values, when recited, includes both theupper and lower limits of the range as well as any sub-rangestherebetween. As used herein, the indefinite articles “a,” “an,” and thecorresponding definite article “the” mean “at least one” or “one ormore,” unless otherwise specified. It also is understood that thevarious features disclosed in the specification and the drawings can beused in any and all combinations.

As used herein, the term “glass-based” is used in its broadest sense toinclude any objects made wholly or partly of glass, including glassceramics (which include a crystalline phase and a residual amorphousglass phase). Unless otherwise specified, all compositions of theglasses described herein are expressed in terms of mole percent (mol %),and the constituents are provided on an oxide basis. Unless otherwisespecified, all temperatures are expressed in terms of degrees Celsius (°C.).

It is noted that the terms “substantially” and “about” may be utilizedherein to represent the inherent degree of uncertainty that may beattributed to any quantitative comparison, value, measurement, or otherrepresentation. These terms are also utilized herein to represent thedegree by which a quantitative representation may vary from a statedreference without resulting in a change in the basic function of thesubject matter at issue. For example, a glass that is “substantiallyfree of K₂O” is one in which K₂O is not actively added or batched intothe glass but may be present in very small amounts as a contaminant,such as in amounts of less than about 0.01 mol %. As utilized herein,when the term “about” is used to modify a value, the exact value is alsodisclosed. For example, the term “greater than about 10 mol %” alsodiscloses “greater than or equal to 10 mol %.”

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying examples and drawings.

The glass-based articles disclosed herein are formed by steam treating aglass-based substrate to produce a compressive stress layer extendingfrom a surface of the article to a depth of compression (DOC). Theglass-based substrate compositions are selected to allow the glass-basedsubstrates to be fusion formed and to avoid the formation of platinumdefects during the forming process, such that the glass-based substratesare fusion formable and platinum compatible. The glass-based substratecompositions and the treatment methods are also selected to avoid theformation of haze on the surface of the glass-based articles. Thecompressive stress layer includes a stress that decreases from a maximumstress to the depth of compression. In some embodiments, the maximumcompressive stress may be located at the surface of the glass-basedarticle. As used herein, depth of compression (DOC) means the depth atwhich the stress in the glass-based article changes from compressive totensile. Thus, the glass-based article also contains a tensile stressregion having a maximum central tension (CT), such that the forceswithin the glass-based article are balanced.

The glass-based articles further include a hydrogen-containing layerextending from a surface of the article to a depth of layer. Thehydrogen-containing layer includes a hydrogen concentration thatdecreases from a maximum hydrogen concentration of the glass-basedarticle to the depth of layer. In some embodiments, the maximum hydrogenconcentration may be located at the surface of the glass-based article.

The glass-based articles may be formed by exposing glass-basedsubstrates to environments containing water vapor, thereby allowinghydrogen species to penetrate the glass-based substrates and form theglass-based articles having a hydrogen-containing layer and/or acompressive stress layer. As utilized herein, the term “hydrogenspecies” includes molecular water, hydroxyl, hydrogen ions, andhydronium. The composition of the glass-based substrates is selected topromote the interdiffusion of hydrogen species into the glass. Asutilized herein, the term “glass-based substrate” refers to theprecursor prior to exposure to a water vapor containing environment forthe formation of a glass-based article that includes hydrogen-containinglayers and/or compressive stress layers. Similarly, the term“glass-based article” refers to the post exposure article that includesa hydrogen-containing layer and/or a compressive stress layer.

The glass-based articles disclosed herein may exhibit a compressivestress layer without undergoing conventional ion exchange, thermaltempering, or lamination treatments. Ion exchange processes producesignificant waste in the form of expended molten salt baths that requirecostly disposal, and also are applicable to only some glasscompositions. Thermal tempering requires thick glass specimens as apractical matter, as thermal tempering of thin sheets utilizes small airgap quenching processes which commonly result in scratch damage,reducing performance and yield. Additionally, it is difficult to achieveuniform compressive stress across surface and edge regions when thermaltempering thin glass sheets. Laminate processes result in exposedtensile stress regions when large sheets are cut to usable sizes, whichis undesirable.

The water vapor treatment utilized to form the glass-based articlesallows for reduced waste and lower cost when compared to ion exchangetreatments, as molten salts are not utilized. The water vapor treatmentis also capable of strengthening thin (<2 mm) glass that would not besuitable for thermal tempering at such thicknesses. Additionally, thewater vapor treatment may be performed at the part level, avoiding theundesirable exposed tensile stress regions associated with laminateprocesses. In sum, the glass-based articles disclosed herein may beproduced with a low thickness and at a low cost while exhibiting a highcompressive stress and deep depth of compression.

A representative cross-section of a glass-based article 100 according tosome embodiments is depicted in FIG. 1. The glass-based article 100 hasa thickness t that extends between a first surface 110 and a secondsurface 112. A first compressive stress layer 120 extends from the firstsurface 110 to a first depth of compression, where the first depth ofcompression has a depth d₁ measured from the first surface 110 into theglass-based article 100. A second compressive stress layer 122 extendsfrom the second surface 112 to a second depth of compression, where thesecond depth of compression has a depth d2 measured from the secondsurface 112 into the glass-based article 100. A tensile stress region130 is present between the first depth of compression and the seconddepth of compression. In embodiments, the first depth of compression d₁may be substantially equivalent or equivalent to the second depth ofcompression d₂.

In some embodiments, the compressive stress layer of the glass-basedarticle may include a compressive stress of greater than or equal to 25MPa, such as greater than or equal to 30 MPa, greater than or equal to40 MPa, greater than or equal to 50 MPa, greater than or equal to 60MPa, greater than or equal to 70 MPa, greater than or equal to 80 MPa,greater than or equal to 90 MPa, greater than or equal to 100 MPa,greater than or equal to 110 MPa, greater than or equal to 120 MPa,greater than or equal to 130 MPa, greater than or equal to 140 MPa,greater than or equal to 145 MPa, greater than or equal to 150 MPa,greater than or equal to 160 MPa, greater than or equal to 170 MPa,greater than or equal to 180 MPa, greater than or equal to 190 MPa,greater than or equal to 200 MPa, greater than or equal to 210 MPa,greater than or equal to 220 MPa, greater than or equal to 230 MPa,greater than or equal to 240 MPa, greater than or equal to 250 MPa,greater than or equal to 260 MPa, greater than or equal to 270 MPa,greater than or equal to 280 MPa, greater than or equal to 290 MPa,greater than or equal to 300 MPa, greater than or equal to 310 MPa,greater than or equal to 320 MPa, greater than or equal to 330 MPa,greater than or equal to 340 MPa, greater than or equal to 350 MPa,greater than or equal to 360 MPa, greater than or equal to 370 MPa,greater than or equal to 380 MPa, greater than or equal to 390 MPa,greater than or equal to 400 MPa, greater than or equal to 410 MPa,greater than or equal to 420 MPa, or more. In some embodiments, thecompressive stress layer may include a compressive stress of fromgreater than or equal to 25 MPa to less than or equal to 450 MPa, suchas from greater than or equal to 30 MPa to less than or equal to 440MPa, from greater than or equal to 40 MPa to less than or equal to 430MPa, from greater than or equal to 50 MPa to less than or equal to 420MPa, from greater than or equal to 60 MPa to less than or equal to 410MPa, from greater than or equal to 70 MPa to less than or equal to 400MPa, from greater than or equal to 80 MPa to less than or equal to 390MPa, from greater than or equal to 90 MPa to less than or equal to 380MPa, from greater than or equal to 100 MPa to less than or equal to 370MPa, from greater than or equal to 110 MPa to less than or equal to 360MPa, from greater than or equal to 120 MPa to less than or equal to 350MPa, from greater than or equal to 130 MPa to less than or equal to 340MPa, from greater than or equal to 140 MPa to less than or equal to 330MPa, from greater than or equal to 150 MPa to less than or equal to 320MPa, from greater than or equal to 160 MPa to less than or equal to 310MPa, from greater than or equal to 170 MPa to less than or equal to 300MPa, from greater than or equal to 180 MPa to less than or equal to 290MPa, from greater than or equal to 190 MPa to less than or equal to 280MPa, from greater than or equal to 200 MPa to less than or equal to 270MPa, from greater than or equal to 210 MPa to less than or equal to 260MPa, from greater than or equal to 220 MPa to less than or equal to 250MPa, from greater than or equal to 220 MPa to less than or equal to 240MPa, or any sub-ranges formed from any of these endpoints.

In some embodiments, the DOC of the compressive stress layer may begreater than or equal to 5 μm, such as greater than or equal to 7 μm,greater than or equal to 10 μm, greater than or equal to 15 μm, greaterthan or equal to 20 μm, greater than or equal to 25 μm, greater than orequal to 30 μm, or more. In some embodiments, the DOC of the compressivestress layer may be from greater than or equal to 5 μm to less than orequal to 100 μm, such as from greater than or equal to 7 μm to less thanor equal to 90 μm, from greater than or equal to 10 μm to less than orequal to 80 μm, from greater than or equal to 15 μm to less than orequal to 70 μm, from greater than or equal to 20 μm to less than orequal to 60 μm, from greater than or equal to 25 μm to less than orequal to 50 μm, from greater than or equal to 30 μm to less than orequal to 40 μm, from greater than or equal to 30 μm to less than orequal to 35 μm, or any sub-ranges that may be formed from any of theseendpoints.

In some embodiments, the glass-based articles may exhibit a deep depthof compression and a high compressive stress. For example, theglass-based articles may have any of the depths of compression andcompressive stresses described herein in combination.

In some embodiments, the glass-based articles may have a DOC greaterthan or equal to 0.05t, wherein t is the thickness of the glass-basedarticle, such as greater than or equal to 0.06t, greater than or equalto 0.07t, greater than or equal to 0.08t, greater than or equal to0.09t, greater than or equal to 0.10t, greater than or equal to 0.11t,greater than or equal to 0.12t, greater than or equal to 0.13t, greaterthan or equal to 0.14t, greater than or equal to 0.15t, greater than orequal to 0.16t, greater than or equal to 0.17t, greater than or equal to0.18t, greater than or equal to 0.19t, or more. In some embodiments, theglass-based articles may have a DOC from greater than or equal to 0.05tto less than or equal to 0.20t, such as from greater than or equal to0.06t to less than or equal to 0.19t, from greater than or equal to0.07t to less than or equal to 0.18t, from greater than or equal to0.08t to less than or equal to 0.17t, from greater than or equal to0.09t to less than or equal to 0.16t, from greater than or equal to0.10t to less than or equal to 0.15t, from greater than or equal to0.11t to less than or equal to 0.14t, from greater than or equal to0.12t to less than or equal to 0.13t, or any sub-ranges formed from anyof these endpoints.

Compressive stress (including surface CS) is measured by surface stressmeter using commercially available instruments such as the FSM-6000(FSM), manufactured by Orihara Industrial Co., Ltd. (Japan). Surfacestress measurements rely upon the accurate measurement of the stressoptical coefficient (SOC), which is related to the birefringence of theglass. SOC in turn is measured according to Procedure C (Glass DiscMethod) described in ASTM standard C770-16, entitled “Standard TestMethod for Measurement of Glass Stress-Optical Coefficient,” thecontents of which are incorporated herein by reference in theirentirety. DOC is measured by FSM. Any maximum central tension (CT)values are measured using a scattered light polariscope (SCALP)technique known in the art.

The hydrogen-containing layer of the glass-based articles may have adepth of layer (DOL) greater than 5 μm. In some embodiments, the depthof layer may be greater than or equal to 10 μm, such as greater than orequal to 15 μm, greater than or equal to 20 μm, greater than or equal to25 μm, greater than or equal to 30 μm, greater than or equal to 35 μm,greater than or equal to 40 μm, greater than or equal to 45 μm, greaterthan or equal to 50 μm, greater than or equal to 55 μm, greater than orequal to 60 μm, greater than or equal to 65 μm, greater than or equal to70 μm, greater than or equal to 75 μm, greater than or equal to 80 μm,greater than or equal to 85 μm, greater than or equal to 90 μm, greaterthan or equal to 95 μm, or more. In some embodiments, the depth of layermay be from greater than 5 μm to less than or equal to 100 μm, such asfrom greater than or equal to 10 μm to less than or equal to 95 μm, fromgreater than or equal to 15 μm to less than or equal to 90 μm, fromgreater than or equal to 20 μm to less than or equal to 85 μm, fromgreater than or equal to 25 μm to less than or equal to 80 μm, fromgreater than or equal to 30 μm to less than or equal to 75 μm, fromgreater than or equal to 35 μm to less than or equal to 70 μm, fromgreater than or equal to 40 μm to less than or equal to 65 μm, fromgreater than or equal to 45 μm to less than or equal to 60 μm, fromgreater than or equal to 50 μm to less than or equal to 55 pm, or anysub-ranges formed by any of these endpoints. The hydrogen depth of layeris greater than or equal to the depth of compression, as measured by theFSM technique described above. In general, the depth of layer exhibitedby the glass-based articles is greater than the depth of layer that maybe produced by exposure to the ambient environment.

The hydrogen-containing layer of the glass-based articles may have adepth of layer (DOL) greater than 0.005t, wherein t is the thickness ofthe glass-based article. In some embodiments, the depth of layer may begreater than or equal to 0.010t, such as greater than or equal to0.015t, greater than or equal to 0.020t, greater than or equal to0.025t, greater than or equal to 0.030t, greater than or equal to0.035t, greater than or equal to 0.040t, greater than or equal to0.045t, greater than or equal to 0.050t, greater than or equal to0.055t, greater than or equal to 0.060t, greater than or equal to0.065t, greater than or equal to 0.070t, greater than or equal to0.075t, greater than or equal to 0.080t, greater than or equal to0.085t, greater than or equal to 0.090t, greater than or equal to0.095t, greater than or equal to 0.10t, greater than or equal to 0.15t,greater than or equal to 0.20t, or more. In some embodiments, the DOLmay be from greater than 0.005t to less than or equal to 0.205t, such asfrom greater than or equal to 0.010t to less than or equal to 0.200t,from greater than or equal to 0.015t to less than or equal to 0.195t,from greater than or equal to 0.020t to less than or equal to 0.190t,from greater than or equal to 0.025t to less than or equal to 0.185t,from greater than or equal to 0.030t to less than or equal to 0.180t,from greater than or equal to 0.035t to less than or equal to 0.175t,from greater than or equal to 0.040t to less than or equal to 0.170t,from greater than or equal to 0.045t to less than or equal to 0.165t,from greater than or equal to 0.050t to less than or equal to 0.160t,from greater than or equal to 0.055t to less than or equal to 0.155t,from greater than or equal to 0.060t to less than or equal to 0.150t,from greater than or equal to 0.065t to less than or equal to 0.145t,from greater than or equal to 0.070t to less than or equal to 0.140t,from greater than or equal to 0.075t to less than or equal to 0.135t,from greater than or equal to 0.080t to less than or equal to 0.130t,from greater than or equal to 0.085t to less than or equal to 0.125t,from greater than or equal to 0.090t to less than or equal to 0.120t,from greater than or equal to 0.095t to less than or equal to 0.115t,from greater than or equal to 0.100t to less than or equal to 0.110t, orany sub-ranges formed by any of these endpoints.

The depth of layer and hydrogen concentration are measured by asecondary ion mass spectrometry (SIMS) technique that is known in theart. The SIMS technique is capable of measuring the hydrogenconcentration at a given depth but is not capable of distinguishing thehydrogen species present in the glass-based article. For this reason,all hydrogen species contribute to the SIMS measured hydrogenconcentration. As utilized herein, the depth of layer (DOL) refers tothe first depth below the surface of the glass-based article where thehydrogen concentration is equal to the hydrogen concentration at thecenter of the glass-based article. This definition accounts for thehydrogen concentration of the glass-based substrate prior to treatment,such that the depth of layer refers to the depth of the hydrogen addedby the treatment process. As a practical matter, the hydrogenconcentration at the center of the glass-based article may beapproximated by the hydrogen concentration at the depth from the surfaceof the glass-based article where the hydrogen concentration becomessubstantially constant, as the hydrogen concentration is not expected tochange between such a depth and the center of the glass-based article.This approximation allows for the determination of the DOL withoutmeasuring the hydrogen concentration throughout the entire depth of theglass-based article. The presence of the hydrogen-containing layer maybe indicated by the formation of a compressive stress layer in theglass-based article as a result of the water vapor treatment.

Without wishing to be bound by any particular theory, thehydrogen-containing layer of the glass-based articles may be the resultof an interdiffusion of hydrogen species for ions contained in thecompositions of the glass-based substrate. Hydrogen-containing species,such as H₃O⁺, H₂O, and/or H⁺, may diffuse into the glass-based substrateto form the glass-based article. Water could penetrate the glass-basedsubstrates by forming silanol groups, breaking the network structure andcausing a volume expansion of the glass. Such a volume expansion maygenerate a compressive stress layer in the glass-based articles. Thecompressive stress and depth of compression of the compressive stresslayer may depend on the composition of the glass-based substrateutilized to form the glass-based article, and the water vapor treatmentconditions, such as temperature, pressure, water content, and duration.The stress profile of the glass-based articles produced by the watervapor treatment may be similar to stress profiles produced by potassiumfor sodium ion exchange strengthening processes.

The glass-based articles that have compressive stress layers alsoexhibit weight gain when compared to the glass-based substrates prior tothe water vapor treatment process. The weight gain of the glass-basedarticles indicates the formation of a hydrogen-containing layer as aresult of the water vapor treatment. The amount of weight gain isdirectly related to the amount of hydrogen species that enter theglass-based article as a result of the water vapor treatment process.

The glass-based articles disclosed herein may be incorporated intoanother article such as an article with a display (or display articles)(e.g., consumer electronics, including mobile phones, tablets,computers, navigation systems, wearable devices (e.g., watches) and thelike), architectural articles, transportation articles (e.g.,automotive, trains, aircraft, sea craft, etc.), appliance articles, orany article that requires some transparency, scratch-resistance,abrasion resistance or a combination thereof An exemplary articleincorporating any of the glass-based articles disclosed herein is shownin FIGS. 2A and 2B. Specifically, FIGS. 2A and 2B show a consumerelectronic device 200 including a housing 202 having front 204, back206, and side surfaces 208; electrical components (not shown) that areat least partially inside or entirely within the housing and includingat least a controller, a memory, and a display 210 at or adjacent to thefront surface of the housing; and a cover plate 212 at or over the frontsurface of the housing such that it is over the display. In someembodiments, at least a portion of at least one of the cover plate 212and the housing 202 may include any of the glass-based articlesdisclosed herein.

The glass-based articles may be formed from glass-based substrateshaving any appropriate composition. The composition of the glass-basedsubstrate may be specifically selected to promote the diffusion ofhydrogen-containing species, such that a glass-based article including ahydrogen-containing layer and a compressive stress layer may be formedefficiently, to allow the glass-based articles to be fusion formed, toavoid the formation of platinum defects during the production process,and to avoid the formation of haze as a result of the water vaportreatment process. In some embodiments, the glass-based substrates mayhave a composition that includes SiO₂, Al₂O₃, P₂O₅, K₂O, and optionallyLi₂O. In some embodiments, the hydrogen species does not diffuse to thecenter of the glass-based article. Stated differently, the center of theglass-based article is the area least affected by the water vaportreatment. For this reason, the center of the glass-based article mayhave a composition that is substantially the same, or the same, as thecomposition of the glass-based substrate prior to treatment in the watercontaining environment. The composition at the center of the glass-basedarticle refers to the composition as measured at any point that islocated at a distance of at least 0.5t from every surface of theglass-based article, where t is the thickness of the glass-basedarticle. The composition at the center of the glass-based article may bemeasured by any appropriate process, such as microprobe analysis, andmay be approximated by the composition of the glass-based substrateutilized to form the glass-based article.

The glass-based substrate may include any appropriate amount of SiO₂.SiO₂ is the largest constituent and, as such, SiO₂ is the primaryconstituent of the glass network formed from the glass composition. Ifthe concentration of SiO₂ in the glass composition is too high, theformability of the glass composition may be diminished as higherconcentrations of SiO₂ increase the difficulty of melting the glass,which, in turn, adversely impacts the formability of the glass. In someembodiments, the glass-based substrate may include SiO₂ in an amountfrom greater than or equal to 55.0 mol % to less than or equal to 65.0mol %, such as from greater than or equal to 55.5 mol % to less than orequal to 64.5 mol %, from greater than or equal to 56.0 mol % to lessthan or equal to 64.0 mol %, from greater than or equal to 56.5 mol % toless than or equal to 63.5 mol %, from greater than or equal to 57.0 mol% to less than or equal to 63.0 mol %, from greater than or equal to57.5 mol % to less than or equal to 62.5 mol %, from greater than orequal to 58.0 mol % to less than or equal to 62.0 mol %, from greaterthan or equal to 58.5 mol % to less than or equal to 61.5 mol %, fromgreater than or equal to 59.0 mol % to less than or equal to 61.0 mol %,from greater than or equal to 59.5 mol % to less than or equal to 60.5mol %, from greater than or equal to 60.0 mol % to less than or equal to65.0 mol %, or any sub-ranges formed by any of these endpoints.

The glass-based substrate may include any appropriate amount of Al₂O₃.Al₂O₃ may serve as a glass network former, similar to SiO₂. Al₂O₃ mayincrease the viscosity of the glass composition due to its tetrahedralcoordination in a glass melt formed from a glass composition, decreasingthe formability of the glass composition when the amount of Al₂O₃ is toohigh. However, when the concentration of Al₂O₃ is balanced against theconcentration of SiO₂ and the concentration of alkali oxides in theglass composition, Al₂O₃ can reduce the liquidus temperature of theglass melt, thereby enhancing the liquidus viscosity and improving thecompatibility of the glass composition with certain forming processes,such as the fusion forming process. The inclusion of Al₂O₃ in theglass-based substrate prevents phase separation and reduces the numberof non-bridging oxygens (NBOs) in the glass. Additionally, Al₂O₃ canimprove the effectiveness of ion exchange. In some embodiments, theglass-based substrate may include Al₂O₃ in an amount of from greaterthan or equal to 10.0 mol % to less than or equal to 15.0 mol %, such asfrom greater than or equal to 10.5 mol % to less than or equal to 14.5mol %, from greater than or equal to 11.0 mol % to less than or equal to14.0 mol %, from greater than or equal to 11.5 mol % to less than orequal to 13.5 mol %, from greater than or equal to 12.0 mol % to lessthan or equal to 13.0 mol %, from greater than or equal to 12.5 mol % toless than or equal to 13.0 mol %, or any sub-ranges formed by any ofthese endpoints.

The glass-based substrate may include any amount of P₂O₅ sufficient toproduce the desired hydrogen diffusivity. The inclusion of phosphorousin the glass-based substrate promotes faster interdiffusion. Thus, thephosphorous containing glass-based substrates allow the efficientformation of glass-based articles including a hydrogen-containing layer.The inclusion of P₂O₅ also allows for the production of a glass-basedarticle with a deep depth of layer (e.g., greater than about 10 μm) in arelatively short treatment time. In cases where the amount of P₂O₅ isgreater than 6.0 mol % the glass becomes susceptible to the formation ofplatinum defects when contacting platinum containing formationapparatuses, such as melting and/or fining apparatuses, which arecommonly employed in commercial glass production. Stated differently,when the glass includes greater than 6.0 mol % P₂O₅ the glass is notplatinum compatible. In cases where the amount of P₂O₅ is less than 3.5mol % the glass does not exhibit the desired diffusivity, liquidustemperature, or zircon compatibility. Zircon compatibility is importantfor use with common glass forming apparatuses, such as zircon isopipesin fusion forming equipment. In embodiments, the glass-based substratemay include P₂O₅ in an amount of from greater than or equal to 3.5 mol %to less than or equal to 6.0 mol %, such as from greater than or equalto 3.5 mol % to less than or equal to 5.5 mol %, from greater than orequal to 3.6 mol % to less than or equal to 5.9 mol %, from greater thanor equal to 3.7 mol % to less than or equal to 5.8 mol %, from greaterthan or equal to 3.8 mol % to less than or equal to 5.7 mol %, fromgreater than or equal to 3.9 mol % to less than or equal to 5.6 mol %,from greater than or equal to 4.0 mol % to less than or equal to 5.5 mol%, from greater than or equal to 4.1 mol % to less than or equal to 5.4mol %, from greater than or equal to 4.2 mol % to less than or equal to5.3 mol %, or any sub-ranges formed by any of these endpoints.

The glass-based substrate may include Li₂O in any appropriate amount.Other embodiments of the glass-based substrate do not include anyintentional additions of Li₂O. The inclusion of Li₂O in the glass-basedsubstrate increases the resistance of the glass-based article to hazeformation as a result of steam strengthening. The content of Li₂O in theglass-based substrate is directly correlated with a reduction in the 200P temperature of the glass-based substrate, such that the inclusion ofLi₂O improves the meltability of the glass. The content of Li₂O in theglass-based substrate is also directly correlated to the coefficient ofthermal expansion of the glass-based substrate. In some embodiments, theglass-based substrate may include Li₂O in an amount of from greater thanor equal to 2.0 mol % to less than or equal to 5.0 mol %, such as fromgreater than or equal to 2.1 mol % to less than or equal to 4.9 mol %,from greater than or equal to 2.2 mol % to less than or equal to 4.8 mol%, from greater than or equal to 2.3 mol % to less than or equal to 4.7mol %, from greater than or equal to 2.4 mol % to less than or equal to4.6 mol %, from greater than or equal to 2.5 mol % to less than or equalto 4.5 mol %, from greater than or equal to 2.6 mol % to less than orequal to 4.4 mol %, from greater than or equal to 2.7 mol % to less thanor equal to 4.3 mol %, from greater than or equal to 2.8 mol % to lessthan or equal to 4.2 mol %, from greater than or equal to 2.9 mol % toless than or equal to 4.1 mol %, from greater than or equal to 3.0 mol %to less than or equal to 4.0 mol %, from greater than or equal to 3.1mol % to less than or equal to 3.9 mol %, from greater than or equal to3.2 mol % to less than or equal to 3.8 mol %, from greater than or equalto 3.3 mol % to less than or equal to 3.7 mol %, from greater than orequal to 3.4 mol % to less than or equal to 3.6 mol %, from greater thanor equal to 3.0 mol % to less than or equal to 3.5 mol %, or any and allsub-ranges formed from these endpoints.

The glass-based substrate may include K₂O in any appropriate amount. Theinclusion of K₂O in the glass-based substrate increases the steamstrengthening susceptibility of the glass-based article to a greaterdegree than other alkali metal oxides. In some embodiments, theglass-based substrate may include K₂O in an amount of from greater thanor equal to 6.0 mol % to less than or equal to 15.0 mol %, such as fromgreater than or equal to 6.5 mol % to less than or equal to 14.5 mol %,from greater than or equal to 7.0 mol % to less than or equal to 14.0mol %, from greater than or equal to 7.5 mol % to less than or equal to13.5 mol %, from greater than or equal to 8.0 mol % to less than orequal to 13.0 mol %, from greater than or equal to 8.5 mol % to lessthan or equal to 12.5 mol %, from greater than or equal to 9.0 mol % toless than or equal to 12.0 mol %, from greater than or equal to 9.5 mol% to less than or equal to 11.5 mol %, from greater than or equal to10.0 mol % to less than or equal to 11.0 mol %, from greater than orequal to 10.5 mol % to less than or equal to 11.0 mol %, or any and allsub-ranges formed from these endpoints.

The glass-based substrate may include Na₂O in any appropriate amount. Insome embodiments, the glass-based substrate may include Na₂O in anamount of from greater than or equal to 0 mol % to less than or equal to11.0 mol %, such as from greater than or equal to 0.5 mol % to less thanor equal to 10.5 mol %, from greater than or equal to 1.0 mol % to lessthan or equal to 9.0 mol %, from greater than or equal to 1.5 mol % toless than or equal to 8.5 mol %, from greater than or equal to 2.0 mol %to less than or equal to 8.0 mol %, from greater than or equal to 2.5mol % to less than or equal to 7.5 mol %, from greater than or equal to3.0 mol % to less than or equal to 7.0 mol %, from greater than or equalto 3.5 mol % to less than or equal to 6.5 mol %, from greater than orequal to 4.0 mol % to less than or equal to 6.0 mol %, from greater thanor equal to 4.5 mol % to less than or equal to 5.5 mol %, from greaterthan or equal to 4.0 mol % to less than or equal to 5.0 mol %, or anyand all sub-ranges formed from these endpoints. In embodiments, theglass-based substrate may be substantially free or free of Na₂O.

The glass-based substrates may additionally include B₂O₃. The inclusionof B₂O₃ in the glass-based substrates may increase the damage resistanceof the glass-based substrates, and thereby increase the damageresistance of the glass-based articles formed therefrom. In someembodiments, the glass-based substrates may include B₂O₃ in an amountfrom greater than or equal to 0 mol % to less than or equal to 10.0 mol%, such as from greater than or equal to 0.5 mol % to less than or equalto 9.5 mol %, from greater than or equal to 1.0 mol % to less than orequal to 9.0 mol %, from greater than or equal to 1.5 mol % to less thanor equal to 8.5 mol %, from greater than or equal to 2.0 mol % to lessthan or equal to 8.0 mol %, from greater than or equal to 2.5 mol % toless than or equal to 7.5 mol %, from greater than or equal to 3.0 mol %to less than or equal to 7.0 mol %, from greater than or equal to 3.5mol % to less than or equal to 6.5 mol %, from greater than or equal to4.0 mol % to less than or equal to 6.0 mol %, from greater than or equalto 4.5 mol % to less than or equal to 5.5 mol %, from greater than orequal to 4.0 mol % to less than or equal to 5.0 mol %, from greater thanor equal to 0.0 mol % to less than or equal to 3.0 mol %, or any and allsub-ranges formed from these endpoints. In embodiments, the glass-basedsubstrates may be substantially free or free of B₂O₃.

The glass-based substrates may additionally include a fining agent. Insome embodiments, the fining agent may include tin. In embodiments, theglass-based substrate may include SnO₂ in an amount from greater than orequal to 0 mol % to less than or equal to 0.5 mol %, such as fromgreater than 0 mol % to less than or equal to 0.1 mol %, or any and allsub-ranges formed from these endpoints. In embodiments, the glass-basedsubstrate may be substantially free or free of SnO₂.

The glass-based substrate may be characterized by a R₂O/Al₂O₃ molarratio, wherein R₂O is the total amount of monovalent metal oxides, suchas alkali metal oxides. In some embodiments, the glass-based substratehas a R₂O/Al₂O₃ molar ratio of less than or equal to 1.4, such as lessthan or equal to 1.3, less than or equal to 1.2, less than or equal to1.1, or less. In some embodiments, the glass-based substrate has aR₂O/Al₂O₃ molar ratio of from greater than or equal to 1.0 to less thanor equal to 1.4, such as from greater than or equal to 1.1 to less thanor equal to 1.4, from greater than or equal to 1.2 to less than or equalto 1.3, or any and all sub-ranges formed from these endpoints.Maintaining a R₂O/Al₂O₃ molar ratio of the glass-based substrate of lessthan or equal to 1.4 avoids the undesired formation of a second glassyphase in the glass-based substrate, commonly referred to as phaseseparation.

The glass-based substrate may also be characterized by a(R₂O+P₂O₅)/Al₂O₃ molar ratio, wherein R₂O is the total amount ofmonovalent metal oxides, such as alkali metal oxides. In someembodiments, the glass-based substrate has a (R₂O+P₂O₅)/Al₂O₃ molarratio of greater than 1.4 and less than 1.9, such as 1.41 to 1.89, 1.425to 1.875, 1.45 to 1.85, and all values and sub-ranges between thesevalues. In some embodiments, the glass-based substrate has a(R₂O+P₂O₅)/Al₂O₃ molar ratio of 1.41, 1.42, 1.43, 1.44, 1.45, 1.5, 1.55,1.6, 1.65, 1.70, 1.75, 1.80, 1.85, 1.86, 1.87, 1.88, 1.89, and allvalues between 1.4 and 1.9. Maintaining a (R₂O+P₂O₅)/Al₂O₃ molar ratioof the glass-based substrate between 1.4 and 1.9 also avoids phaseseparation.

The glass-based substrate may be characterized by an average fieldstrength of alkali modifiers. The field strength of the glass-basedsubstrate is calculated according to the following formula:

$\frac{Z}{\left( {r_{A} + r_{O}} \right)^{2}}$

where Z is the alkali modifier charge (fixed at 1), r_(A) is the ionicradius of the alkali ion in angstroms, and r_(o) is the ionic radius ofoxygen in angstroms. The calculated field strength was 0.23 for Li, 0.19for Na, and 0.13 for K. The average field strength of the alkalimodifiers for the glass-based substrates is calculated as a weightedaverage based on the total alkali content. In embodiments, theglass-based substrates have an average field strength of the alkalimodifiers of less than or equal to 0.18, such as less than or equal to0.17, less than or equal to 0.16, less than or equal to 0.15, or less.In cases where the average field strength of the alkali modifiers in theglass-based substrate is less than or equal to 0.18 the glass-basedsubstrates are resistant to phase separation, particularly where the R₂Ocontent is greater than the Al₂O₃ content. In embodiments, theglass-based substrates have an average field strength of the alkalimodifiers from greater than or equal to 0.14 to less than or equal to0.18, such as from greater than or equal to 0.15 to less than or equalto 0.17, from greater than or equal to 0.16 to less than or equal to0.18, or any and all sub-ranges formed from these endpoints.

In some embodiments, the glass-based substrates include Li₂O and P₂O₅,or P₂O₅ and no Li₂O, without exhibiting phase separation. As usedherein, “phase separation”, “phase-separated glass” or the like refer toa glass-based substrate which experiences the formation of a secondglassy phase. Further, a “phase-separated glass” can be identified by anoptical measurement using a spectrophotometer and/or SEM analysis. As tothe former, a “phase separated glass” is any glass or glass-basedsubstrate that exhibits greater than 0.2% diffuse transmission and/orscatter ratio (i.e., % diffuse transmission/% transmittance*100) at awavelength of 300 nm with a test sample of the glass or glass-basedsubstrate having a thickness of 1 mm. As to the latter, SEM analysis ata magnification of about 100kx on a cross-sectioned glass-basedsubstrate can be employed to ascertain phase separation. Phaseseparation is undesirable in the glass-based substrates, as phaseseparation may result in a milky and/or bluish appearance of theglass-based substrates. The composition of the glass-based substratesmay be specifically selected to avoid phase separation. For example, theglass-based substrates may have a composition selected such that theR₂O/Al₂O₃ molar ratio and the average field strength of the alkalimodifiers are within the ranges described herein to prevent phaseseparation.

In embodiments, the glass-based substrates are compatible with platinum.This compatibility allows the glass-based substrates to be melted,fined, and formed using platinum containing apparatuses withoutproducing globular chain platinum defects in the glass-based substrates.As utilized herein, a “globular chain platinum defect” refers toglobular chain platinum observed in the glass-based substrates with asize of greater than 100 μm, as measured through optical microscopy withreflected light and/or scanning electron microscopy energy-dispersivex-ray (SEM-EDX) analysis. Further, the observed globular chain platinumis typically in the form of inclusions with two or more connectedsegments that appear ‘globular’. These segments may be well-spaced orconnected on multiple surfaces and wrapped closely. Further, the“globular chain platinum defects” herein are measured by opticalmicroscopy and/or SEM-EDX inspection of glass-based substrates and arenormalized by the total weight of the glass inspected to produce adefects per pound value. The size of the globular chain platinum isdefined by the largest dimension thereof. According to some embodiments,the globular chain defects can include platinum and one or more ofrhodium, tin and iron. In embodiments, the glass-based substratesinclude less than 1 globular chain platinum defect per pound, such asbeing substantially free of globular chain platinum defects, or free ofglobular chain platinum defects.

In some embodiments, the glass-based substrates may have a Young'smodulus that is greater than or equal to 50 GPa. In embodiments, theglass-based substrates have a Young's modulus that is greater than orequal to 51 GPa, such as greater than or equal to 52 GPa, greater thanor equal to 53 GPa, greater than or equal to 54 GPa, greater than orequal to 55 GPa, greater than or equal to 56 GPa, greater than or equalto 57 GPa, greater than or equal to 58 GPa, greater than or equal to 59GPa, greater than or equal to 60 GPa, greater than or equal to 61 GPa,greater than or equal to 62 GPa, greater than or equal to 63 GPa,greater than or equal to 64 GPa, greater than or equal to 65 GPa, ormore. In some embodiments, the glass-based substrates may have a Young'smodulus in the range from greater than or equal to 50 GPa to less thanor equal to 70 GPa, such as from greater than or equal to 51 GPa to lessthan or equal to 69 GPa, from greater than or equal to 52 GPa to lessthan or equal to 68 GPa, from greater than or equal to 53 GPa to lessthan or equal to 67 GPa, from greater than or equal to 54 GPa to lessthan or equal to 66 GPa, from greater than or equal to 55 GPa to lessthan or equal to 65 GPa, from greater than or equal to 56 GPa to lessthan or equal to 64 GPa, from greater than or equal to 57 GPa to lessthan or equal to 63 GPa, from greater than or equal to 58 GPa to lessthan or equal to 62 GPa, from greater than or equal to 59 GPa to lessthan or equal to 61 GPa, from greater than or equal to 59 GPa to lessthan or equal to 60 GPa, or any and all sub-ranges formed from theseendpoints.

In some embodiments, the glass-based substrates may have a 200 Ptemperature of less than or equal to 1725° C., such as less than orequal to 1720° C., less than or equal to 1715° C., less than or equal to1710° C., less than or equal to 1705° C., less than or equal to 1700°C., less than or equal to 1695° C., less than or equal to 1690° C., lessthan or equal to 1685° C., less than or equal to 1680° C., less than orequal to 1675° C., less than or equal to 1670° C., less than or equal to1665° C., less than or equal to 1660° C., less than or equal to 1655°C., less than or equal to 1650° C., less than or equal to 1645° C., lessthan or equal to 1640° C., less than or equal to 1635° C., less than orequal to 1630° C., less than or equal to 1625° C., less than or equal to1620° C., less than or equal to 1615° C., less than or equal to 1610°C., less than or equal to 1605° C., less than or equal to 1600° C., orless. The low 200 P temperature improves the meltability and therebymanufacturability of the glass-based substrate compositions.

In some embodiments, the glass-based substrates may have a liquidusviscosity of greater than or equal to 10 kP, such as greater than orequal to 100 kP, greater than or equal to 1000 kP, or more. Increases inthe Li₂O content of the glass-based substrate decrease the liquidusviscosity of the glass-based substrate composition. Maintaining theliquidus viscosity of the glass-based substrate at greater than about 10kP allows the glass-based substrates to be produced on a variety ofmanufacturing platforms, such as fusion forming platforms. It isparticularly preferred that the glass-based substrates have a liquidusviscosity of greater than or equal to 100 kP to ensure compatibilitywith fusion forming. If the liquidus viscosity decreases too much, themanufacturability of the glass-based substrates is decreased.

In some embodiments, the glass-based substrates may have zirconbreakdown viscosity of less than or equal to 35 kP, such as less than orequal to 30 kP, less than or equal to 25 kP, less than or equal to 20kP, less than or equal to 19 kP, less than or equal to 18 kP, less thanor equal to 17 kP, less than or equal to 16 kP, less than or equal to 15kP, less than or equal to 14 kP, less than or equal to 13 kP, less thanor equal to 12 kP, less than or equal to 11 kP, less than or equal to 10kP, less than or equal to 9 kP, less than or equal to 8 kP, less than orequal to 7 kP, less than or equal to 6 kP, less than or equal to 5 kP,less than or equal to 4 kP, less than or equal to 3 kP, less than orequal to 2 kP, less than or equal to 1 kP, or less. The zircon breakdownviscosity is the viscosity of the glass at the zircon breakdowntemperature. Maintaining the zircon breakdown viscosity in the range ofless than or equal to 35 kP ensures that the composition is compatiblewith fusion forming processes that utilize zircon containing elements,such as zircon isopipes.

The glass-based substrate may have any appropriate geometry. In someembodiments, the glass-based substrate may have a thickness of less thanor equal to 2.0 mm, such as less than or equal to 1.9 mm, less than orequal to 1.8 mm, less than or equal to 1.7 mm, less than or equal to 1.6mm, less than or equal to 1.5 mm, less than or equal to 1.4 mm, lessthan or equal to 1.3 mm, less than or equal to 1.2 mm, less than orequal to 1.1 mm, less than or equal to 1 mm, less than or equal to 900μm, less than or equal to 800 μm, less than or equal to 700 μm, lessthan or equal to 600 μm, less than or equal to 500 μm, less than orequal to 400 μm, less than or equal to 300 μm, or less. In embodiments,the glass-based substrate may have a thickness from greater than orequal to 300 μm to less than or equal to 2 mm, such as from greater thanor equal to 400 μm to less than or equal to 1.9 mm, from greater than orequal to 500 μm to less than or equal to 1.8 mm, from greater than orequal to 600 μm to less than or equal to 1.7 mm, from greater than orequal to 700 μm to less than or equal to 1.6 mm, from greater than orequal to 800 μm to less than or equal to 1.5 mm, from greater than orequal to 900 μm to less than or equal to 1.4 mm, from greater than orequal to 1 mm to less than or equal to 1.3 mm, from greater than orequal to 1.1 mm to less than or equal to 1.2 mm, or any and allsub-ranges formed from these endpoints. In some embodiments, theglass-based substrate may have a plate or sheet shape. In some otherembodiments, the glass-based substrates may have a 2.5D or 3D shape. Asutilized herein, a “2.5D shape” refers to a sheet shaped article with atleast one major surface being at least partially nonplanar, and a secondmajor surface being substantially planar. As utilized herein, a “3Dshape” refers to an article with first and second opposing majorsurfaces that are at least partially nonplanar. The glass-based articlesmay have dimensions and shapes substantially similar or the same as theglass-based substrates from which they are formed.

The glass-based substrates may be formed by any suitable method, such asslot forming, float forming, rolling processes, fusion formingprocesses, etc. The glass-based substrates, and glass-based articlesproduced therefrom, may be characterized by the manner in which they areformed. For instance, a glass-based substrate may be characterized asfloat-formable (i.e., formed by a float process), down-drawable and, inparticular, fusion-formable or slot-drawable (i.e., formed by a downdraw process such as a fusion draw process or a slot draw process).

Some embodiments of the glass-based substrates described herein may beformed by a down-draw process. Down-draw processes produce glass-basedsubstrates having a uniform thickness that possess relatively pristinesurfaces. Because the average flexural strength of the glass-basedsubstrate is controlled by the amount and size of surface flaws, apristine surface that has had minimal contact has a higher initialstrength. In addition, down drawn glass-based substrates have a veryflat, smooth surface that can be used in its final application withoutcostly grinding and polishing.

Some embodiments of the glass-based substrates may be described asfusion-formable (i.e., formable using a fusion draw process). The fusiondraw process uses a drawing tank that has a channel for accepting moltenglass raw material. The channel has weirs that are open at the top alongthe length of the channel on both sides of the channel. When the channelfills with molten material, the molten glass overflows the weirs. Due togravity, the molten glass flows down the outside surfaces of the drawingtank as two flowing glass films. These outside surfaces of the drawingtank extend down and inwardly so that they join at an edge below thedrawing tank. The two flowing glass films join at this edge to fuse andform a single flowing glass article. The fusion of the glass filmsproduces a fusion line within the glass-based substrate, and this fusionline allows glass-based substrates that were fusion formed to beidentified without additional knowledge of the manufacturing history.The fusion draw method offers the advantage that, because the two glassfilms flowing over the channel fuse together, neither of the outsidesurfaces of the resulting glass article comes in contact with any partof the apparatus. Thus, the surface properties of the fusion drawn glassarticle are not affected by such contact.

The compositions of the glass-based substrates described herein arespecifically selected to be compatible with the fusion forming process.This compatibility is dependent on the liquidus viscosity and zirconbreakdown viscosity of the composition of the glass-based substrates. Inembodiments, the glass-based substrates have a liquidus viscosity ofgreater than or equal to 100 kP and a zircon breakdown viscosity of lessthan or equal to 35 kP.

Some embodiments of the glass-based substrates described herein may beformed by a slot draw process. The slot draw process is distinct fromthe fusion draw method. In slot draw processes, the molten raw materialglass is provided to a drawing tank. The bottom of the drawing tank hasan open slot with a nozzle that extends the length of the slot. Themolten glass flows through the slot/nozzle and is drawn downward as acontinuous glass-based substrate and into an annealing region.

The glass-based articles may be produced from the glass-based substrateby exposure to water vapor under any appropriate conditions. Theexposure may be carried out in any appropriate device, such as a furnacewith relative humidity control. The exposure may also be carried out atan elevated pressure, such as in a furnace or autoclave with relativehumidity and pressure control.

In some embodiments, the glass-based articles may be produced byexposing a glass-based substrate to an environment with a pressuregreater than ambient pressure and containing water vapor. Theenvironment may have a pressure greater than 0.1 MPa and a water partialpressure of greater than or equal to 0.05 MPa, such as greater than orequal to 0.075 MPa. The elevated pressure in the exposure environmentallows for a higher concentration of water vapor in the environment,especially as temperatures are increased. As the temperature increasesthe amount of water available for diffusion into the glass-basedsubstrates to form glass-based articles decreases for a fixed volume,such as the interior of a furnace or autoclave. Thus, while increasingthe temperature of the water vapor treatment environment may increasethe rate of diffusion of hydrogen species into the glass-basedsubstrate, reduced total water vapor concentration and stress relaxationat higher temperatures produce decreased compressive stress whenpressure remains constant. As temperatures increase, such as those abovethe atmospheric pressure saturation condition, applying increasedpressure to reach the saturation condition increases the concentrationof water vapor in the environment significantly.

At atmospheric pressure (0.1 MPa), the water vapor saturation conditionis 99.61° C. As the temperature increases the amount of water availablefor diffusion into the glass-based substrates to form glass-basedarticles decreases for a fixed volume, such as the interior of a furnaceor autoclave. Thus, while increasing the temperature of the water vaportreatment environment may increase the rate of diffusion of hydrogenspecies into the glass-based substrate, reduced total water vaporconcentration may reduce the effectiveness of the treatment.

As temperatures increase, such as those above the atmospheric pressuresaturation condition, applying increased pressure to reach thesaturation condition increases the concentration of water vapor in theenvironment significantly. The saturation condition for water vapor as afunction of pressure and temperature is shown in FIG. 3. As shown inFIG. 3, the regions above the curve will result in condensation of watervapor into liquid which is undesirable. Thus, the water vapor treatmentconditions utilized herein may preferably fall on or under the curve inFIG. 3, with further preferred conditions being on or just under thecurve to maximize water vapor content. For these reasons, the watervapor treatment of the glass-based substrates may be carried out atelevated pressure.

High temperature and pressure conditions have been shown to produceglass-based articles with a hazy appearance. The hazy appearance iscorrelated to the concentration of added hydrogen species in theglass-based article, with higher temperature and pressure conditionsproducing higher concentrations of hydrogen species in the glass-basedarticle. The formation of haze during the water treatment process may beaddressed by utilizing the lithium containing compositions describedherein or by selecting the treatment conditions to manage the amount ofhydrogen species added to the glass-based article. For example, at hightemperatures treatment pressures below the saturation pressure may beutilized to reduce the concentration of hydrogen species in theglass-based article. The concentration of the hydrogen species may bereduced by decreasing the total amount of hydrogen species diffused intothe glass-based article, as evidenced by reduced weight gain duringwater vapor treatment, or by increasing the depth of layer for the sameamount of weight gain. The approaches for mitigating haze, compositionand treatment conditions may be utilized in conjunction.

In some embodiments, the lithium containing glass-based substratesdescribed herein may be exposed to a water vapor treatment in asaturated steam environment at a temperature of greater than or equal to85° C. The glass-based substrates containing lithium allow the use of awider process window with higher temperatures and pressures whileavoiding haze, thereby decreasing treatment times and increasing theefficiency of the strengthening process. The glass-based articlesproduced utilizing these haze mitigation strategies are substantiallyhaze-free or haze-free in appearance.

In some embodiments, the glass-based substrates may be exposed to anenvironment at a pressure greater than or equal to 0.1 MPa, such asgreater than or equal to 0.2 MPa, greater than or equal to 0.3 MPa,greater than or equal to 0.4 MPa, greater than or equal to 0.5 MPa,greater than or equal to 0.6 MPa, greater than or equal to 0.7 MPa,greater than or equal to 0.8 MPa, greater than or equal to 0.9 MPa,greater than or equal to 1.0 MPa, greater than or equal to 1.1 MPa,greater than or equal to 1.2 MPa, greater than or equal to 1.3 MPa,greater than or equal to 1.4 MPa, greater than or equal to 1.5 MPa,greater than or equal to 1.6 MPa, greater than or equal to 1.7 MPa,greater than or equal to 1.8 MPa, greater than or equal to 1.9 MPa,greater than or equal to 2.0 MPa, greater than or equal to 2.1 MPa,greater than or equal to 2.2 MPa, greater than or equal to 2.3 MPa,greater than or equal to 2.4 MPa, greater than or equal to 2.5 MPa,greater than or equal to 2.6 MPa, greater than or equal to 2.7 MPa,greater than or equal to 2.8 MPa, greater than or equal to 2.9 MPa,greater than or equal to 3.0 MPa, greater than or equal to 3.1 MPa,greater than or equal to 3.2 MPa, greater than or equal to 3.3 MPa,greater than or equal to 3.4 MPa, greater than or equal to 3.5 MPa,greater than or equal to 3.6 MPa, greater than or equal to 3.7 MPa,greater than or equal to 3.8 MPa, greater than or equal to 3.9 MPa,greater than or equal to 4.0 MPa, greater than or equal to 4.1 MPa,greater than or equal to 4.2 MPa, greater than or equal to 4.3 MPa,greater than or equal to 4.4 MPa, greater than or equal to 4.5 MPa,greater than or equal to 4.6 MPa, greater than or equal to 4.7 MPa,greater than or equal to 4.8 MPa, greater than or equal to 4.9 MPa,greater than or equal to 5.0 MPa, greater than or equal to 5.1 MPa,greater than or equal to 5.2 MPa, greater than or equal to 5.3 MPa,greater than or equal to 5.4 MPa, greater than or equal to 5.5 MPa,greater than or equal to 5.6 MPa, greater than or equal to 5.7 MPa,greater than or equal to 5.8 MPa, greater than or equal to 5.9 MPa,greater than or equal to 6.0 MPa, or more. In embodiments, theglass-based substrates may be exposed to an environment at a pressure offrom greater than or equal to 0.1 MPa to less than or equal to 25 MPa,such as from greater than or equal to 0.2 MPa to less than or equal to24 MPa, from greater than or equal to 0.3 MPa to less than or equal to23 MPa, from greater than or equal to 0.4 MPa to less than or equal to22 MPa, from greater than or equal to 0.5 MPa to less than or equal to21 MPa, from greater than or equal to 0.6 MPa to less than or equal to20 MPa, from greater than or equal to 0.7 MPa to less than or equal to19 MPa, from greater than or equal to 0.8 MPa to less than or equal to18 MPa, from greater than or equal to 0.9 MPa to less than or equal to17 MPa, from greater than or equal to 1.0 MPa to less than or equal to16 MPa, from greater than or equal to 1.1 MPa to less than or equal to15 MPa, from greater than or equal to 1.2 MPa to less than or equal to14 MPa, from greater than or equal to 1.3 MPa to less than or equal to13 MPa, from greater than or equal to 1.4 MPa to less than or equal to12 MPa, from greater than or equal to 1.5 MPa to less than or equal to11 MPa, from greater than or equal to 1.6 MPa to less than or equal to10 MPa, from greater than or equal to 1.7 MPa to less than or equal to 9MPa, from greater than or equal to 1.8 MPa to less than or equal to 8MPa, from greater than or equal to 1.9 MPa to less than or equal to 7MPa, from greater than or equal to 1.9 MPa to less than or equal to 6.9MPa, from greater than or equal to 2.0 MPa to less than or equal to 6.8MPa, from greater than or equal to 2.1 MPa to less than or equal to 6.7MPa, from greater than or equal to 2.2 MPa to less than or equal to 6.6MPa, from greater than or equal to 2.3 MPa to less than or equal to 6.5MPa, from greater than or equal to 2.4 MPa to less than or equal to 6.4MPa, from greater than or equal to 2.5 MPa to less than or equal to 6.3MPa, from greater than or equal to 2.6 MPa to less than or equal to 6.2MPa, from greater than or equal to 2.7 MPa to less than or equal to 6.1MPa, from greater than or equal to 2.8 MPa to less than or equal to 6.0MPa, from greater than or equal to 2.9 MPa to less than or equal to 5.9MPa, from greater than or equal to 3.0 MPa to less than or equal to 5.8MPa, from greater than or equal to 3.1 MPa to less than or equal to 5.7MPa, from greater than or equal to 3.2 MPa to less than or equal to 5.6MPa, from greater than or equal to 3.3 MPa to less than or equal to 5.5MPa, from greater than or equal to 3.4 MPa to less than or equal to 5.4MPa, from greater than or equal to 3.5 MPa to less than or equal to 5.3MPa, from greater than or equal to 3.6 MPa to less than or equal to 5.2MPa, from greater than or equal to 3.7 MPa to less than or equal to 5.1MPa, from greater than or equal to 3.8 MPa to less than or equal to 5.0MPa, from greater than or equal to 3.9 MPa to less than or equal to 4.9MPa, from greater than or equal to 4.0 MPa to less than or equal to 4.8MPa, from greater than or equal to 4.1 MPa to less than or equal to 4.7MPa, from greater than or equal to 4.2 MPa to less than or equal to 4.6MPa, from greater than or equal to 4.3 MPa to less than or equal to 4.5MPa, 4.4 MPa, or any and all sub-ranges formed from any of theseendpoints. In some embodiments, the glass-based substrates may beexposed to an environment at ambient pressure, such as 0.1 MPa.

In some embodiments, the glass-based substrates may be exposed to anenvironment with a water partial pressure greater than or equal to 0.05MPa, such as greater than or equal to 0.075 MPa, greater than or equalto 0.1 MPa, greater than or equal to 0.2 MPa, greater than or equal to0.3 MPa, greater than or equal to 0.4 MPa, greater than or equal to 0.5MPa, greater than or equal to 0.6 MPa, greater than or equal to 0.7 MPa,greater than or equal to 0.8 MPa, greater than or equal to 0.9 MPa,greater than or equal to 1.0 MPa, greater than or equal to 1.1 MPa,greater than or equal to 1.2 MPa, greater than or equal to 1.3 MPa,greater than or equal to 1.4 MPa, greater than or equal to 1.5 MPa,greater than or equal to 1.6 MPa, greater than or equal to 1.7 MPa,greater than or equal to 1.8 MPa, greater than or equal to 1.9 MPa,greater than or equal to 2.0 MPa, greater than or equal to 2.1 MPa,greater than or equal to 2.2 MPa, greater than or equal to 2.3 MPa,greater than or equal to 2.4 MPa, greater than or equal to 2.5 MPa,greater than or equal to 2.6 MPa, greater than or equal to 2.7 MPa,greater than or equal to 2.8 MPa, greater than or equal to 2.9 MPa,greater than or equal to 3.0 MPa, greater than or equal to 3.1 MPa,greater than or equal to 3.2 MPa, greater than or equal to 3.3 MPa,greater than or equal to 3.4 MPa, greater than or equal to 3.5 MPa,greater than or equal to 3.6 MPa, greater than or equal to 3.7 MPa,greater than or equal to 3.8 MPa, greater than or equal to 3.9 MPa,greater than or equal to 4.0 MPa, greater than or equal to 4.1 MPa,greater than or equal to 4.2 MPa, greater than or equal to 4.3 MPa,greater than or equal to 4.4 MPa, greater than or equal to 4.5 MPa,greater than or equal to 4.6 MPa, greater than or equal to 4.7 MPa,greater than or equal to 4.8 MPa, greater than or equal to 4.9 MPa,greater than or equal to 5.0 MPa, greater than or equal to 5.1 MPa,greater than or equal to 5.2 MPa, greater than or equal to 5.3 MPa,greater than or equal to 5.4 MPa, greater than or equal to 5.5 MPa,greater than or equal to 5.6 MPa, greater than or equal to 5.7 MPa,greater than or equal to 5.8 MPa, greater than or equal to 5.9 MPa,greater than or equal to 6.0 MPa, greater than or equal to 7.0 MPa,greater than or equal to 8.0 MPa, greater than or equal to 9.0 MPa,greater than or equal to 10.0 MPa, greater than or equal to 11.0 MPa,greater than or equal to 12.0 MPa, greater than or equal to 13.0 MPa,greater than or equal to 14.0 MPa, greater than or equal to 15.0 MPa,greater than or equal to 16.0 MPa, greater than or equal to 17.0 MPa,greater than or equal to 18.0 MPa, greater than or equal to 19.0 MPa,greater than or equal to 20.0 MPa, greater than or equal to 21.0 MPa,greater than or equal to 22.0 MPa, or more. In embodiments, theglass-based substrates may be exposed to an environment with a waterpartial pressure from greater than or equal to 0.05 MPa to less than orequal to 22 MPa, such as from greater than or equal to 0.075 MPa to lessthan or equal to 22 MPa, from greater than or equal to 0.1 MPa to lessthan or equal to 21 MPa, from greater than or equal to 0.2 MPa to lessthan or equal to 20 MPa, from greater than or equal to 0.3 MPa to lessthan or equal to 19 MPa, from greater than or equal to 0.4 MPa to lessthan or equal to 18 MPa, from greater than or equal to 0.5 MPa to lessthan or equal to 17 MPa, from greater than or equal to 0.6 MPa to lessthan or equal to 16 MPa, from greater than or equal to 0.7 MPa to lessthan or equal to 15 MPa, from greater than or equal to 0.8 MPa to lessthan or equal to 14 MPa, from greater than or equal to 0.9 MPa to lessthan or equal to 13 MPa, from greater than or equal to 1.0 MPa to lessthan or equal to 12 MPa, from greater than or equal to 1.1 MPa to lessthan or equal to 11 MPa, from greater than or equal to 1.2 MPa to lessthan or equal to 10 MPa, from greater than or equal to 1.3 MPa to lessthan or equal to 9 MPa, from greater than or equal to 1.4 MPa to lessthan or equal to 8 MPa, from greater than or equal to 1.5 MPa to lessthan or equal to 7 MPa, from greater than or equal to 1.6 MPa to lessthan or equal to 6.9 MPa, from greater than or equal to 1.7 MPa to lessthan or equal to 6.8 MPa, from greater than or equal to 1.8 MPa to lessthan or equal to 6.7 MPa, from greater than or equal to 1.9 MPa to lessthan or equal to 6.6 MPa, from greater than or equal to 2.0 MPa to lessthan or equal to 6.5 MPa, from greater than or equal to 2.1 MPa to lessthan or equal to 6.4 MPa, from greater than or equal to 2.2 MPa to lessthan or equal to 6.3 MPa, from greater than or equal to 2.3 MPa to lessthan or equal to 6.2 MPa, from greater than or equal to 2.4 MPa to lessthan or equal to 6.1 MPa, from greater than or equal to 2.5 MPa to lessthan or equal to 6.0 MPa, from greater than or equal to 2.6 MPa to lessthan or equal to 5.9 MPa, from greater than or equal to 2.7 MPa to lessthan or equal to 5.8 MPa, from greater than or equal to 2.8 MPa to lessthan or equal to 5.7 MPa, from greater than or equal to 2.9 MPa to lessthan or equal to 5.6 MPa, from greater than or equal to 3.0 MPa to lessthan or equal to 5.5 MPa, from greater than or equal to 3.1 MPa to lessthan or equal to 5.4 MPa, from greater than or equal to 3.2 MPa to lessthan or equal to 5.3 MPa, from greater than or equal to 3.3 MPa to lessthan or equal to 5.2 MPa, from greater than or equal to 3.4 MPa to lessthan or equal to 5.1 MPa, from greater than or equal to 3.5 MPa to lessthan or equal to 5.0 MPa, from greater than or equal to 3.6 MPa to lessthan or equal to 4.9 MPa, from greater than or equal to 3.7 MPa to lessthan or equal to 4.8 MPa, from greater than or equal to 3.8 MPa to lessthan or equal to 4.7 MPa, from greater than or equal to 3.9 MPa to lessthan or equal to 4.6 MPa, from greater than or equal to 4.0 MPa to lessthan or equal to 4.5 MPa, from greater than or equal to 4.1 MPa to lessthan or equal to 4.4 MPa, from greater than or equal to 4.2 MPa to lessthan or equal to 4.3 MPa, or any and all sub-ranges formed from any ofthese endpoints.

In some embodiments, the glass-based substrates may be exposed to anenvironment with a relative humidity of greater than or equal to 10%,such as greater than or equal to 25%, greater than or equal to 50%,greater than or equal to 75%, greater than or equal to 80%, greater thanor equal to 85%, greater than or equal to 90%, greater than or equal to95%, greater than or equal to 99%, or more. In some embodiments, theglass-based substrate may be exposed to an environment with 100%relative humidity. In some embodiments, the environment may be asaturated steam environment.

In some embodiments, the glass-based substrates may be exposed to anenvironment with a temperature of greater than or equal to 85° C., suchas greater than or equal to 90° C., greater than or equal to 100° C.,greater than or equal to 110° C., greater than or equal to 120° C.,greater than or equal to 130° C., greater than or equal to 140° C.,greater than or equal to 150° C., greater than or equal to 160° C.,greater than or equal to 170° C., greater than or equal to 180° C.,greater than or equal to 190° C., greater than or equal to 200° C.,greater than or equal to 210° C., greater than or equal to 220° C.,greater than or equal to 230° C., greater than or equal to 240° C.,greater than or equal to 250° C., greater than or equal to 260° C.,greater than or equal to 270° C., greater than or equal to 280° C.,greater than or equal to 290° C., greater than or equal to 300° C.,greater than or equal to 310° C., greater than or equal to 320° C.,greater than or equal to 330° C., greater than or equal to 340° C.,greater than or equal to 350° C., greater than or equal to 360° C.,greater than or equal to 370° C., greater than or equal to 380° C.,greater than or equal to 390° C., greater than or equal to 400° C., ormore. In some embodiments, the glass-based substrates may be exposed toan environment with a temperature from greater than or equal to 85° C.to less than or equal to 400° C., such as from greater than or equal to100° C. to less than or equal to 390° C., from greater than or equal to110° C. to less than or equal to 380° C., from greater than or equal to115° C. to less than or equal to 370° C., from greater than or equal to120° C. to less than or equal to 360° C., from greater than or equal to125° C. to less than or equal to 350° C., from greater than or equal to130° C. to less than or equal to 340° C., from greater than or equal to135° C. to less than or equal to 330° C., from greater than or equal to140° C. to less than or equal to 320° C., from greater than or equal to145° C. to less than or equal to 310° C., from greater than or equal to150° C. to less than or equal to 300° C., from greater than or equal to155° C. to less than or equal to 295° C., from greater than or equal to160° C. to less than or equal to 290° C., from greater than or equal to165° C. to less than or equal to 285° C., from greater than or equal to170° C. to less than or equal to 280° C., from greater than or equal to175° C. to less than or equal to 275° C., from greater than or equal to180° C. to less than or equal to 270° C., from greater than or equal to185° C. to less than or equal to 265° C., from greater than or equal to190° C. to less than or equal to 260° C., from greater than or equal to195° C. to less than or equal to 255° C., from greater than or equal to200° C. to less than or equal to 250° C., from greater than or equal to205° C. to less than or equal to 245° C., from greater than or equal to210° C. to less than or equal to 240° C., from greater than or equal to215° C. to less than or equal to 235° C., from greater than or equal to220° C. to less than or equal to 230° C., from greater than or equal to220° C. to less than or equal to 225° C., or any and all sub-rangesformed from any of these endpoints.

In some embodiments, the glass-based substrate may be exposed to thewater vapor containing environment for a time period sufficient toproduce the desired degree of hydrogen-containing species diffusion andthe desired compressive stress layer. In some embodiments, theglass-based substrate may be exposed to the water vapor containingenvironment for greater than or equal to 2 hours, such as greater thanor equal to 4 hours, greater than or equal to 6 hours, greater than orequal to 8 hours, greater than or equal to 10 hours, greater than orequal to 12 hours, greater than or equal to 14 hours, greater than orequal to 16 hours, greater than or equal to 18 hours, greater than orequal to 20 hours, greater than or equal to 22 hours, greater than orequal to 24 hours, greater than or equal to 30 hours, greater than orequal to 36 hours, greater than or equal to 42 hours, greater than orequal to 48 hours, greater than or equal to 54 hours, greater than orequal to 60 hours, greater than or equal to 66 hours, greater than orequal to 72 hours, greater than or equal to 78 hours, greater than orequal to 84 hours, greater than or equal to 90 hours, greater than orequal to 96 hours, greater than or equal to 102 hours, greater than orequal to 108 hours, greater than or equal to 114 hours, greater than orequal to 120 hours, greater than or equal to 126 hours, greater than orequal to 132 hours, greater than or equal to 138 hours, greater than orequal to 144 hours, greater than or equal to 150 hours, greater than orequal to 156 hours, greater than or equal to 162 hours, greater than orequal to 168 hours, or more. In some embodiments, the glass-basedsubstrate may be exposed to the water vapor containing environment for atime period from greater than or equal to 2 hours to less than or equalto 10 days, such as from greater than or equal to 4 hours to less thanor equal to 9 days, from greater than or equal to 6 hours to less thanor equal to 8 days, from greater than or equal to 8 hours to less thanor equal to 168 hours, from greater than or equal to 10 hours to lessthan or equal to 162 hours, from greater than or equal to 12 hours toless than or equal to 156 hours, from greater than or equal to 14 hoursto less than or equal to 150 hours, from greater than or equal to 16hours to less than or equal to 144 hours, from greater than or equal to18 hours to less than or equal to 138 hours, from greater than or equalto 20 hours to less than or equal to 132 hours, from greater than orequal to 22 hours to less than or equal to 126 hours, from greater thanor equal to 24 hours to less than or equal to 120 hours, from greaterthan or equal to 30 hours to less than or equal to 114 hours, fromgreater than or equal to 36 hours to less than or equal to 108 hours,from greater than or equal to 42 hours to less than or equal to 102hours, from greater than or equal to 48 hours to less than or equal to96 hours, from greater than or equal to 54 hours to less than or equalto 90 hours, from greater than or equal to 60 hours to less than orequal to 84 hours, from greater than or equal to 66 hours to less thanor equal to 78 hours, 72 hours, or any and all sub-ranges formed fromany of these endpoints.

In some embodiments, the glass-based substrates may be exposed tomultiple water vapor containing environments. In embodiments, theglass-based substrate may be exposed to a first environment to form afirst glass-based article with a first compressive stress layerextending from a surface of the first glass-based article to a firstdepth of compression, and the first glass-based article may then beexposed to a second environment to form a second glass-based articlewith a second compressive stress layer extending from a surface of thesecond glass-based article to a second depth of compression. The firstenvironment has a first water partial pressure and a first temperature,and the glass-based substrate is exposed to the first environment for afirst time period. The second environment has a second water partialpressure and a second temperature, and the first glass-based article isexposed to the second environment for a second time period.

The first water partial pressure and the second water partial pressuremay be any appropriate partial pressure, such as greater than or equalto 0.05 MPa or greater than or equal to 0.075 MPa. The first and secondpartial pressure may be any of the values disclosed herein with respectto the water partial pressures employed in the treatment method. Inembodiments, the first and second environments may have, independently,a relative humidity of greater than or equal to 10%, such as greaterthan or equal to 25%, greater than or equal to 50%, greater than orequal to 75%, greater than or equal to 80%, greater than or equal to90%, greater than or equal to 95%, or equal to 100%. In someembodiments, at least one of the first environment and the secondenvironment has a relative humidity of 100%. In embodiments, the firstand second environments may be, independently, a saturated steamenvironment.

The first compressive stress layer includes a first maximum compressivestress, and the second compressive stress layer includes a secondmaximum compressive stress. In embodiments, the first maximumcompressive stress is less than the second maximum compressive stress.The second maximum compressive stress may be compared to a compressivestress “spike” of the type formed through multi-step or mixed bath ionexchange techniques. The first and second maximum compressive stress mayhave any of the values disclosed herein with respect to the compressivestress of the glass-based article. In embodiments, the second maximumcompressive stress may be greater than or equal to 50 MPa.

The first depth of compression may be less than or equal to the seconddepth of compression. In some embodiments, the first depth ofcompression is less than the second depth of compression. The firstdepth of compression and the second depth of compression may have any ofthe values disclosed herein with respect to the depth of compression. Inembodiments, the second depth of compression is greater than 5 μm.

The first temperature may be greater than or equal to the secondtemperature. In embodiments, the first temperature is greater than thesecond temperature. The first and second temperatures may be any of thetemperatures disclosed in connection with the treatment method.

The first time period may be less than or equal to the second timeperiod. In embodiments, the first time period is less than the secondtime period. The first and second time periods may be any of the timeperiods disclosed in connection with the elevated pressure method.

In embodiments, any or all of the multiple exposures to a water vaporcontaining environment may be performed at an elevated pressure. Forexample, at least one of the first environment and the secondenvironment may have a pressure greater than 0.1 MPa. The first andsecond environments may have any pressure disclosed in connection withthe treatment method.

In some embodiments, the multiple water vapor environment exposuretechnique may include more than two exposure environments. Inembodiments, the second glass-based article may be exposed to a thirdenvironment to form a third glass-based article. The third environmenthas a third water partial pressure and a third temperature, and thesecond glass-based article is exposed to the third environment for athird time period. The third glass-based article includes a thirdcompressive stress layer extending from a surface of the article to athird depth of compression and having a third maximum compressivestress. The third water partial pressure may be greater than or equal to0.05 MPa or greater than or equal to 0.075 MPa. The values of any of theproperties of the third environment and third glass-based article may beselected from those disclosed for the corresponding properties inconnection with the elevated pressure method.

In some embodiments, the first glass-based article may be cooled toambient temperature or otherwise removed from the first environmentafter the conclusion of the first time period and prior to being exposedto the second environment. In some embodiments, the first glass-basedarticle may remain in the first environment after the conclusion of thefirst time period, and the first environment conditions may be changedto the second environment conditions without cooling to ambienttemperature or removing the first glass-based article from the watervapor containing environment.

The methods of producing the glass-based articles disclosed herein maybe free of an ion exchange treatment with an alkali ion source. Inembodiments, the glass-based articles are produced by methods that donot include an ion exchange with an alkali ion source. Stateddifferently, in some embodiments the glass-based substrates andglass-based articles are not subjected to an ion exchange treatment withan alkali ion source.

The exposure conditions may be modified to reduce the time necessary toproduce the desired amount of hydrogen-containing species diffusion intothe glass-based substrate. For example, the temperature and/or relativehumidity may be increased to reduce the time required to achieve thedesired degree of hydrogen-containing species diffusion and depth oflayer into the glass-based substrate.

The methods and glass-based substrate compositions disclosed herein mayproduce glass-based articles that have a substantially haze-free orhaze-free appearance.

Exemplary Embodiments

Glass compositions that are particularly suited for formation of theglass-based articles described herein were formed into glass-basedsubstrates, and the glass compositions are provided in Table I below(Exs. A-V). The density of the glass compositions was determined usingthe buoyancy method of ASTM C693-93(2013). The strain point and annealpoint were determined using the beam bending viscosity method of ASTMC598-93(2013). The Young's modulus values refer to values as measured bya resonant ultrasonic spectroscopy technique of the general type setforth in ASTM E2001-13, titled “Standard Guide for Resonant UltrasoundSpectroscopy for Defect Detection in Both Metallic and Non-metallicParts.” The stress optical coefficient (SOC) was measured according toProcedure C (Glass Disc Method) described in ASTM standard C770-16,entitled “Standard Test Method for Measurement of Glass Stress-OpticalCoefficient.” The refractive index was measured at a wavelength of 589.3nm. The liquidus temperature was measured in accordance with ASTMC829-81(2015), titled “Standard Practice for Measurement of LiquidusTemperature of Glass by the Gradient Furnace Method.” The liquidusviscosity was calculated from the measured liquidus temperature (T) viathe equation:

${\log_{10}\mspace{11mu}\eta} = {A + \frac{B}{T - T_{0}}}$

where η is viscosity, and A, B and T₀ were fitted from high-temperatureviscosity (HTV) measurement, which is measured by rotation viscometersaccording to ASTM C965-96(2012), titled “Standard Practice for MeasuringViscosity of Glass Above the Softening Point.” The zircon breakdowntemperature was measured in the same manner as the liquidus temperatureby positioning a zircon refractory strip in the Pt/Rh boat surrounded byglass cullet. After a testing time of 72 hours the test slab wasexamined by polarized light microscopy, reflective light microscopy, andscanning electron microscopy to detect secondary zirconia and determinethe temperature at which zirconia was produced. The zircon breakdownviscosity is calculated based on the measured zircon breakdowntemperature in the same manner as the liquidus viscosity describedabove.

TABLE I Composition (mol %) Ex. A Ex. B Ex. C Ex. D Ex. E Ex. F Ex. GEx. H SiO₂ 60.7 60.9 61.0 60.5 60.9 61.0 62.3 62.2 Al₂O₃ 12.0 12.0 12.112.0 12.0 12.1 12.9 12.9 P₂O₅ 5.5 5.4 5.5 5.4 5.4 5.4 5.3 5.3 B₂O₃ 9.28.3 7.4 9.3 8.2 7.2 1.6 2.6 Li₂O 3.0 3.8 4.5 2.3 3.0 3.8 3.7 3.7 Na₂O0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 K₂O 9.5 9.4 9.4 10.4 10.4 10.4 14.1 13.1SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Average field 0.15 0.16 0.16 0.150.15 0.16 0.15 0.15 strength R₂O/Al₂O₃ 1.04 1.10 1.16 1.06 1.11 1.171.38 1.30 (R₂O + P₂O₅)/Al₂O₃ 1.50 1.55 1.61 1.52 1.56 1.62 1.79 1.72Density (g/cm³) 2.318 2.327 2.331 2.322 2.331 2.338 2.385 2.375 StrainPt (° C.) 476 476 ** 483 481 484 600 574 Anneal Pt (° C.) 525 524 ** 534530 531 663 634 200 P 1651 1629 1600 1667 1647 1612 1716 1717Temperature (° C.) 35 kP 1147 1129 1094 1173 1137 1105 1218 1217Temperature (° C.) 100 kP 1074 1056 1026 1099 1066 1037 1149 1146Temperature (° C.) Zircon >1375 1370 1370 1355 1355 ** 1255 1295Breakdown Temperature (° C.) Zircon <2.32 2.0 1.3 3.8 2.6 ** 20.9 12.3Breakdown Viscosity (kP) Liquidus <760 <815 <800 <805 <880 ** 1240 1135Temperature (° C.) Liquidus >43955 >8128 >10467 >21613 >2857 ** 26 119Viscosity (kP) Young's Modulus 57.0 58.4 ** 55.9 57.5 58.5 60.9 60.3(GPa) Stress Optical 3.561 3.572 ** ** 3.459 3.383 ** 3.139 Coefficient(nm/mm/MPa) Refractive Index 1.4875 1.4856 ** 1.485 1.4883 1.4868 1.4911.4903 (@589.3 nm) Appearance Non- Non- Non- Non- Non- Non- Non- Non-phase phase phase phase phase phase phase phase separated separatedseparated separated separated separated separated separated Composition(mol %) Ex. I Ex. J Ex. K Ex. L Ex. M Ex. N Ex. O Ex. P SiO₂ 62.5 62.462.5 62.4 62.4 62.4 62.4 62.5 Al₂O₃ 13.0 12.9 13.0 13.0 13.0 13.0 12.913.0 P₂O₅ 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 B₂O₃ 3.0 3.5 4.0 4.5 5.0 5.51.6 1.6 Li₂O 3.5 3.5 3.5 3.6 3.6 3.5 3.6 3.6 Na₂O 0.0 0.0 0.0 0.0 0.00.0 1.8 3.8 K₂O 12.5 12.0 11.4 11.0 10.5 10.0 12.1 10.1 SnO₂ 0.1 0.1 0.10.1 0.1 0.1 0.1 0.1 Average field 0.15 0.15 0.15 0.15 0.16 0.16 0.160.16 strength R₂O/Al₂O₃ 1.23 1.20 1.16 1.12 1.09 1.05 1.35 1.34 (R₂O +P₂O₅)/Al₂O₃ 1.65 1.62 1.57 1.54 1.51 1.47 1.77 1.76 Density (g/cm³)2.396 2.363 2.357 ** ** ** 2.39 2.39 Strain Pt (° C.) 557 541 534 516512 500 588 578 Anneal Pt (° C.) 616 600 592 572 567 554 651 641 200 P1716 1705 ** 1718 1699 ** 1698 1694 Temperature (° C.) 35 kP 1218 1210** 1213 1192 ** 1200 1193 Temperature (° C.) 100 kP 1147 1140 ** 11401122 ** 1132 1123 Temperature (° C.) Zircon 1285 1310 13001320 >1310 >1325 1290 1295 Breakdown Temperature (° C.) Zircon 14.1 9.3** 8.9 <7.5 ** 10.3 9.0 Breakdown Viscosity (kP) Liquidus 1080 980 925910 <820 <780 1160 1075 Temperature (° C.) Liquidus 306 1754 **6543 >61004 ** 64 223 Viscosity (kP) Young's Modulus 60.2 60.0 59.8 59.659.4 59.3 62.9 64.4 (GPa) Stress Optical 3.156 3.209 3.226 3.263 3.3043.37 3.042 3.004 Coefficient (nm/mm/MPa) Refractive Index 1.4899 1.48921.4887 1.4882 1.4877 1.4873 1.4914 1.4917 (@589.3 nm) Appearance Non-Non- Non- Non- Non- Non- Non- Non- phase phase phase phase phase phasephase phase separated separated separated separated separated separatedseparated separated Composition (mol %) Ex. Q Ex. R Ex. S Ex. T Ex. UEx. V SiO₂ 62.5 62.6 62.7 62.3 62.6 62.4 Al₂O₃ 13.0 13.0 13.0 13.0 13.313.3 P₂O₅ 5.4 5.3 5.3 5.4 5.5 5.3 B₂O₃ 1.5 2.5 2.5 2.6 0.0 0.0 Li₂O 3.53.5 3.5 3.5 2.5 0.0 Na₂O 5.8 1.8 3.8 5.8 8.9 11.4 K₂O 8.2 11.1 9.1 7.27.2 7.3 SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 Average field 0.17 0.16 0.17 0.170.17 0.17 strength R₂O/Al₂O₃ 1.35 1.26 1.25 1.28 1.40 1.40 (R₂O +P₂O₅)/Al₂O₃ 1.76 1.67 1.66 1.69 1.81 1.80 Density (g/cm³) 2.393 2.3772.378 2.381 2.406 2.413 Strain Pt (° C.) 566 559 554 538 609 605 AnnealPt (° C.) 628 622 616 597 668 663 200 P 1675 1703 1706 1674 1675 1701Temperature (° C.) 35 kP 1176 1209 1198 1176 1191 1222 Temperature (°C.) 100 kP 1107 1138 1127 1107 1123 1114 Temperature (° C.) Zircon 12951270 1295 1330 1250 >1225 Breakdown Temperature (° C.) Zircon 7.2 15.39.8 4.9 15.5 ** Breakdown Viscosity (kP) Liquidus 955 1035 945 905 995995 Temperature (° C.) Liquidus 1713 571 2912 4649 985 2052 Viscosity(kP) Young's Modulus 65.5 62.7 62.8 65.1 65.02 64.05 (GPa) StressOptical ** 3.072 ** ** 2.998 2.995 Coefficient (nm/mm/MPa) RefractiveIndex 1.4918 1.4906 1.4908 1.4911 1.4912 1.49 (@589.3 nm) AppearanceNon- Non- Non- Non- Non- Non- phase phase phase phase phase phaseseparated separated separated separated separated separated

Samples having the compositions shown in Table I (Ex. A-T) were exposedto water vapor containing environments to form glass articles havingcompressive stress layers. The samples were exposed to steam treatmentat a pressure of 1.6 MPa, and a temperature of 200° C., for a durationof 16 hours. The exposure environments were saturated. The resultingmaximum compressive stress and depth of compression as measured bysurface stress meter (FSM) are reported in Table II. If the stressoptical coefficient (SOC) and/or refractive index (RI) were notavailable, default values of 3.0 nm/mm/MPa and 1.5 were used,respectively. The depth of the hydrogen containing layer in the treatedarticles was greater than or equal to the measured depth of compression(DOC).

TABLE II Composition CS (MPa) DOC (microns) A 249 10 B 268 9 D 233 12 E255 10 F 286 10 G 323 18 H 302 16 I 297 15 J 293 14 K 277 14 L 300 12 M287 11 N 288 12 O 299 15 P 319 12 Q 328 10 R 310 12 S 345 10 T 395 8

Samples having the compositions shown in Table I (Exs. G-T) were exposedto water vapor containing environments to form glass articles havingcompressive stress layers. The samples were exposed to steam treatmentat a pressure of 2.6 MPa, and a temperature of 225° C., for a durationof 16 hours. The exposure environments were saturated. The resultingmaximum compressive stress and depth of compression as measured bysurface stress meter (FSM) are reported in Table III. If the stressoptical coefficient (SOC) and/or refractive index (RI) were notavailable, default values of 3.0 nm/mm/MPa and 1.5 were used,respectively. The depth of the hydrogen containing layer in the treatedarticles was greater than or equal to the measured depth of compression(DOC).

TABLE III Composition CS (MPa) DOC (microns) G 312 26 H 290 22 I 288 21L 260 17 N 248 16 O 299 21 P 318 18 Q 324 15 R 307 17 S 313 14 T 327 12

Samples having the compositions shown in Table I (Exs. D-T) were exposedto water vapor containing environments to form glass articles havingcompressive stress layers. The samples were exposed to steam treatmentat a pressure of 0.76 MPa, and a temperature of 175° C., for a durationof 96 hours. The resulting maximum compressive stress and depth ofcompression as measured by surface stress meter (FSM) are reported inTable IV. If the stress optical coefficient (SOC) and/or refractiveindex (RI) were not available, default values of 3.0 nm/mm/MPa and 1.5were used, respectively. The depth of the hydrogen containing layer inthe treated articles was greater than or equal to the measured depth ofcompression (DOC).

TABLE IV Composition CS (MPa) DOC (microns) D 292 12 G 337 20 H 334 17 I344 15 J 335 14 K 338 14 L 331 12 M 335 11 N 317 11 O 351 15 P 375 11 Q418 9 R 350 12 S 381 9 T 423 7

Samples having the compositions shown in Table I (Exs. A-T) were exposedto water vapor containing environments to form glass articles havingcompressive stress layers. The samples were exposed to steam treatmentat a pressure of 0.1 MPa, and a temperature of 300° C., for a durationof 16 hours. The resulting maximum compressive stress and depth ofcompression as measured by surface stress meter (FSM) are reported inTable V. If the stress optical coefficient (SOC) and/or refractive index(RI) were not available, default values of 3.0 nm/mm/MPa and 1.5 wereused, respectively. The depth of the hydrogen containing layer in thetreated articles was greater than or equal to the measured depth ofcompression (DOC).

TABLE V Composition CS (MPa) DOC (microns) A 55 17 B 42 16 D 45 21 E 4318 F 39 18 G 46 33 H 43 26 I 39 32 J 38 26 L 38 25 M 36 24 O 40 30 P 3924 Q 43 23 R 36 29 S 37 24 T 41 21

Comparative Examples were prepared with the compositions shown in TableVI (Comp. Exs. 1-5). The comparative examples were produced on a glassmelting apparatus by gradually modifying the composition of the glassmelt to arrive at the desired composition. All comparative examplecompositions included significant amounts of globular chain platinumdefects, except for comparative example 4 which did not includesufficient phosphorous to produce the desired hydrogen speciesdiffusivity and was determined to be incompatible with zirconapparatuses at fusion forming viscosities, also due to insufficientphosphorous content. Also, each of these comparative glass compositionsexhibited a R₂O/Al₂O₃ ratio of greater than 1.4 and, with the exceptionof comparative example 4, a (R₂O+P₂O₅)/Al₂O₃ ratio of greater than 1.9.

TABLE VI Composition Comp. Comp. Comp. Comp. Comp. (mol %) Ex. 1 Ex. 2Ex. 3 Ex. 4 Ex. 5 SiO₂ 60.3 62.1 60.1 59.7 60.8 Al₂O₃ 12.8 11.2 10.715.0 11.1 P₂O₅ 7.8 9.4 9.5 3.8 9.4 B₂O₃ 0.6 0.0 0.0 0.0 0.0 Li₂O 3.1 2.70.8 0.0 0.0 Na₂O 0.1 0.1 0.1 11.8 18.4 K₂O 15.2 14.3 18.5 9.5 0.1 SnO₂0.1 0.1 0.1 0.1 0.1 ZrO₂ 0.1 0.1 0.1 0.1 0.1 R₂O/Al₂O₃ 1.44 1.53 1.811.42 1.67 (R₂O + P₂O₅)/Al₂O₃ 2.05 2.37 2.70 1.67 2.51 Globular Chain 145119 127 0 121 Platinum Defects (per pound)

The measured globular chain platinum defects (per pound) as a functionof phosphorous (P₂O₅) content is shown in FIG. 4. As shown in FIG. 4,glasses with P₂O₅ contents in excess of about 6 mol % containproblematic globular chain platinum defects. The globular chain platinumdefect measurements were performed on glass strips, the strips had awidth of 12 cm, a length of 50 cm, and a thickness of 0.4 cm and weighedabout 1.25 pounds. The observed number of defects were then normalizedby the weight of the glass inspected to produce the reported number ofglobular chain platinum defects per pound. A globular chain platinumdefect as detected at 10× magnification is shown in FIG. 5.

Additional Comparative Examples were prepared with the compositionsshown in Table VII (Comp. Exs. 6A-6F) below. The comparative exampleswere produced on a glass melting apparatus by gradually modifying thecomposition of the glass melt to arrive at the desired composition. Allof these comparative example compositions included substantial amountsof phase separation. Also, each of these comparative glass compositionsexhibited a R₂O/Al₂O₃ ratio of greater than 1.4 and a (R₂O+P₂O₅)/Al₂O₃ratio of greater than 1.9.

TABLE VII Composition Comp. Ex. Comp. Ex. Comp. Ex. Comp. Ex. Comp. Ex.Comp. Ex. (mol %) 6A 6B 6C 6D 6E 6F SiO₂ 61.9 61.9 61.9 61.9 61.9 61.9Al₂O₃ 13 13 13 13 13 13 P₂O₅ 5.5 5.5 5.5 5.5 5.5 5.5 Li₂O 3.5 3.5 3.53.5 3.5 3.5 Na₂O 2.5 3.5 4.5 5.5 6.5 7.5 K₂O 13.5 12.5 11.5 10.5 9.5 8.5SnO₂ 0.1 0.1 0.1 0.1 0.1 0.1 R₂O/Al₂O₃ 1.50 1.50 1.50 1.50 1.50 1.50(R₂O + P₂O₅)/Al₂O₃ 1.92 1.92 1.92 1.92 1.92 1.92 Appearance Phase-Phase- Phase- Phase- Phase- Phase- separated separated separatedseparated separated separated

FIG. 6A is a plot of diffuse scattering in transmission (%) vs.wavelength (i.e., 300 nm to 850 nm) for an inventive glass compositionfrom Table I (Ex. V) and comparative glass compositions (Comp. Exs.6A-6F). FIG. 6B is a plot of the scatter ratio (%) vs. wavelength forthese same glass compositions. A UV-Vis-NIR spectrophotometer wasemployed to make the measurements shown in FIGS. 6A and 6B, asconfigured with an integrating sphere or a standard axial detector forsamples having a thickness of 1 mm. While data is reported in FIGS. 6Aand 6B using light wavelengths from 300 nm to 850 nm, data was alsoanalyzed at more typical visible wavelength ranges from 380 to 780 nmand 400 to 700 nm. Further, the diffuse scattering in transmission (%)data shown in FIG. 6A is generated from the spectrophotometer. As to thescatter ratio (%) shown in FIG. 6B, this value is given by the (%T_(diffuse)% T_(total))*100, where T_(diffuse) is the diffusetransmittance shown in FIG. 6A and T_(total) is the total transmittanceof the sample. With regard to the data shown in FIGS. 6A and 6B, it isevident that the comparative glass compositions that exhibit phaseseparation (Comp. Exs. 6A-6F) have both scatter ratio and diffusetransmittance levels well above 0.2% at 300 nm and the inventive glasscomposition (Ex. V) has scatter ratio and diffuse transmittance levels<0.2% at 300 nm. Hence, measured scatter ratio and diffuse transmittancelevels can be employed to quantify the degree of phase separation in theglass compositions of the disclosure. Without being bound by theory, itis expected that the phase-separation threshold of 0.2% will change forsamples having a thickness that differs from the 1 mm samples employed.

Turning now to FIGS. 7A and 7B, these figures are scanning electronicmicroscopy (SEM) images of two comparative glass compositions withevidence of phase separation, Comp. Ex. 6B and Comp. Ex. 6C,respectively (see also Table VII above). These images were generated bycross-sectioning the noted comparative samples, evaporating a conductivecarbon coating on their surfaces, and then using a Zeiss Gemini 450 SEMto image them at 2 kV at a magnification of up to 100kx. As is evidentfrom these SEM images, the secondary phase is in the range of about 10to 40 nm for these comparative glass compositions.

While typical embodiments have been set forth for the purpose ofillustration, the foregoing description should not be deemed to be alimitation on the scope of the disclosure or appended claims.Accordingly, various modifications, adaptations, and alternatives mayoccur to one skilled in the art without departing from the spirit andscope of the present disclosure or appended claims.

What is claimed is:
 1. A method, comprising: exposing a glass-basedsubstrate to a treatment environment with a pressure greater than orequal to 0.1 MPa, a water partial pressure of greater than or equal to0.05 MPa, and a temperature greater than 85° C. to form a glass-basedarticle, wherein the glass-based substrate comprises: SiO₂, Al₂O₃, K₂O,R₂O/Al₂O₃ in an amount that is less than or equal to 1.4, wherein R₂O isthe total amount of monovalent metal oxides, greater than or equal to3.5 mol % to less than or equal to 6.0 mol % P₂O₅, and greater than orequal to 2.0 mol % to less than or equal to 5.0 mol % Li₂O, wherein theglass-based article comprises: a compressive stress layer extending froma surface of the glass-based article to a depth of compression, thecompressive stress layer comprising a compressive stress greater than orequal to 25 MPa, a hydrogen-containing layer extending from the surfaceof the glass-based article to a depth of layer, a hydrogen concentrationof the hydrogen-containing layer decreases from a maximum hydrogenconcentration to the depth of layer, and the depth of layer is greaterthan 5 μm.
 2. The method of claim 1, wherein the treatment environmentis a saturated steam environment.
 3. The method of claim 1, wherein thetreatment environment has a pressure greater than or equal to 1 MPa. 4.The method of claim 1, wherein the treatment environment has atemperature greater than or equal to 150° C.
 5. The method of claim 1,further comprising producing the glass-based substrate by a fusionforming process.
 6. The method of claim 1, wherein the glass-basedsubstrate is not subjected to an ion-exchange treatment with an alkaliion source.
 7. The method of claim 1, wherein the glass-based substratefurther comprises B₂O₃.
 8. The method of claim 1, wherein theglass-based substrate further comprises Na₂O.
 9. The method of claim 1,wherein the glass-based substrate further comprises SnO₂.
 10. The methodof claim 1, wherein the glass-based substrate has an average fieldstrength of alkali modifiers that is less than or equal to 0.18.
 11. Themethod of claim 1, wherein the glass-based substrate comprises: greaterthan or equal to 55.0 mol % to less than or equal to 65.0 mol % SiO₂,greater than or equal to 10.0 mol % to less than or equal to 15.0 mol %Al₂O₃, greater than or equal to 0 mol % to less than or equal to 10.0mol % B₂O₃, and greater than or equal to 6.0 mol % to less than or equalto 15.0 mol % K2O.
 12. The method of claim 1, wherein the glass-basedsubstrate comprises greater than or equal to 4.5 mol % to less than orequal to 5.5 mol % P₂O₅.
 13. The method of claim 1, wherein theglass-based substrate comprises greater than 0 mol % to less than orequal to 3.0 mol % B₂O₃.
 14. The method of claim 1, wherein theglass-based substrate comprises a fusion line.
 15. The method of claim1, wherein the glass-based substrate comprises less than 1 globularchain platinum defect per pound.
 16. The method of claim 1, wherein theglass-based substrate has a zircon breakdown viscosity of less than orequal to 35 kP.
 17. The method of claim 1, wherein the glass-basedsubstrate has a liquidus viscosity of greater than or equal to 100 kP.18. The method of claim 1, wherein the glass-based article has asubstantially haze-free appearance.
 19. The method of claim 1, whereinthe depth of compression is greater than 5 μm.
 20. The method of claim1, wherein the compressive stress layer comprises a compressive stressgreater than or equal to 200 MPa.